CN1802229A - Method for producing metal powder - Google Patents
Method for producing metal powder Download PDFInfo
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- CN1802229A CN1802229A CN 200480015808 CN200480015808A CN1802229A CN 1802229 A CN1802229 A CN 1802229A CN 200480015808 CN200480015808 CN 200480015808 CN 200480015808 A CN200480015808 A CN 200480015808A CN 1802229 A CN1802229 A CN 1802229A
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Abstract
A method for producing a metal powder wherein an ion of the metal to be precipitated is reduced by the action of a reducing agent in a liquid reaction system to precipitate the metal powder, which comprises reducing the ion of the metal under a condition wherein the exchange current density of an oxidation-reduction reaction between the ion of the metal and the reducing agent, which is determined by the hybrid electric potential theory, is 100 muA/cm<2> or less, to precipitate the metal. The method allows the production of a metal powder having a reduced particle diameter.
Description
Technical field
The present invention relates to a kind of method of making refining metallic powder.
Background technology
Usually, for example noble metal such as platinum and palladium as the catalyst of fuel cell and waste gas purification (off-gas cleanup).But the amount of tellurian precious metal element is limited, and therefore this situation need reduce the use precious metal element.Thereby, make the catalyst that uses noble metal usually, so that the attritive powder particle deposition is on the surface of for example carbon or inorganic compound carrier granular.Catalytic action mainly occurs in the surface of noble metal.Therefore, in order to reduce the amount of noble metal, and, require the noble metal powder on the carrier particle surface to have smaller particles size and bigger specific area in order to keep its enough activity as catalyst as catalyst with said structure.
Recently, carry out conductive powder printing and operplate printing in order to use ink-jet printer, after deliberation the noble metal powder of use metal dust, particularly gold, silver etc. as the pigment of ink jet (ink-jet ink).The noble metal powder that is used for this purposes also requires to have smaller particles size and narrow particle size distribution, although compare with the requirement to catalyst, this requirement is not too strict.
The refining metallic powder of these types is to make by the high-temperature process method, liquid phase reduction or the vapor phase method that are called infusion process.Especially, liquid phase reduction (promptly in liquid-phase reaction system with the ion of reducing agent reduction metal to be precipitated, so that precipitated metal is a metal dust) because of it is easy to simplified apparatus, is used widely at present.Advised using multiple compound as the reducing agent that uses in the liquid phase reduction.The example of the reducing agent that uses of advising comprise following these:
Aldehyde (patent documentation 1);
Sodium hypophosphite, potassium hypophosphite or ammonium hypophosphite (patent documentation 2);
Ascorbic acid (patent documentation 3);
Thiocarbamide or thioacetamide (patent documentation 4);
Allyl alcohol, hydrazine hydrate and hydrogen (patent documentation 5);
Propargyl alcohol and hydrogen (patent documentation 6);
Alcohol, for example ethanol, and hydrogen (patent documentation 7);
Amine, particularly alkanolamine (patent documentation 8);
Alcohol, for example ethanol (patent documentation 9);
Amino alcohol (patent documentation 10); With
Hydrogen or sodium borohydride (patent documentation 11).
In order to have the metal dust of low particle size by the liquid-phase reduction manufactured, it is effective carrying out reduction reaction and precipitate metal dust with lower speed.Therefore, it is important using the reducing agent that has than lower reducing power.Above-mentioned catalyst is arranged as follows according to reducing power from high to low: sodium borohydride or hydrogen＞hypophosphites reducing agent＞ascorbic acid＞alkanolamine (amino alcohol)＞alcohol (ethanol etc.).
Patent documentation 1: the open No.2-169029 of Japanese unexamined patent (claim 1, the 2nd page of lower-left are listed as the capable and same page bottom right of 16-20 be listed as 13-19 capable)
Patent documentation 2: the open No.2-303541 of Japanese unexamined patent (it is capable and be listed as the 18th row to the 3rd page of upper left the 18th row that is listed as from the 2nd page of bottom right that claim 1, the 2nd page of lower-left are listed as 2-7)
Patent documentation 3: the open No.4-298238 of Japanese unexamined patent (claim 1 and section 0005)
Patent documentation 4: the open No.5-161849 of Japanese unexamined patent (claim 1 and section 0007,0009 and 0010)
Patent documentation 5: the open No.6-31166 of Japanese unexamined patent (claim 1 and section 0005)
Patent documentation 6: the open No.31181 of Japanese unexamined patent (claim 1 and section 0004)
Patent documentation 7: the open No.8-162122 of Japanese unexamined patent (claim 1 and section 0007,0013,0014 and 0017)
Patent documentation 8: the open No.11-80647 of Japanese unexamined patent (claim 14,15 and section 0051)
Patent documentation 9: the open No.2000-107606 of Japanese unexamined patent (claim 1 and section 0009,0017)
Patent documentation 10: the open No.2000-279811 of Japanese unexamined patent (claim 1 and section 0013)
Patent documentation 11: the open No.2002-231255 of Japanese unexamined patent (claim 3 and section 0014)
Summary of the invention
Problem to be solved by this invention
As result of study, the inventor finds, also is not that the particle size of sufficiently little and metal dust can further reduce according to the particle size of using the metal dust of the method manufacturing of disclosed reducing agent in these patent documentations.
The purpose of this invention is to provide a kind of new method of making the particle size metal dust littler than conventional powder.
The mode of dealing with problems
According to the inventor's research, in liquid phase reduction, the reduction of metal dust and precipitation reaction roughly are divided into following process:
(1) nucleation process is when the metal ion that will be reduced takes place when hypersaturated state is returned saturation state in liquid phase;
(2) adsorption process, wherein the metal ion in the liquid phase is attracted on the nuclear of generation;
(3) mass transport process, wherein in liquid phase reducing agent near metal ion;
(4) electronic transfer process, wherein reducing agent offers metal ion with its electronics; And
(5) mass transport process, wherein oxidized reducing agent leaves near the reduced metal by the electronics transfer.
In order to reduce the particle size of metal dust, effective ways are the growths that produce the nuclear of maximum possible and suppress nuclear in process (1) in each process of process (2)-(5).Can increase the quantity of the nuclear that generates in the process (1) by the temperature of the concentration of metal ion or liquid phase in the control liquid phase.These conditions when conventional liquid phase reduction is carried out in research also are common.
Understand from the low ionization tendency aspect of precious metal ion, it is very incidental reaction that precious metal ion is reduced into metallic state.Because the reducing power of reducing agent is low more, the electronics transfer is carried out slow more in the process (4), therefore in the past after deliberation following method, thereby in the method by using the above-mentioned reducing agent electronics that slows down shift to suppress the growth of nuclear, so that reduce the particle size of metal dust with lower reducing power.But the reducing power that only reduces reducing agent has limited effect with the particle size that reduces metal dust.Therefore, need to suppress the carrying out of other process, thereby compare, further reduce the particle size of metal dust with stock size.
The inventor from then on viewpoint sets out and has carried out various researchs.The result, the inventor finds, by the nucleus growth in process of inhibition (2)-(5) generally, compare the particle size that can reduce metal dust to a greater degree with the common metal powder particle, described inhibition nucleus growth realizes by carrying out liquid phase reduction under the following conditions: the exchange current density of the redox reaction between metal ion and the reducing agent is 100 μ A/cm
2Or it is littler.Can determine exchange current density according to mixed potential theory (mixed potential theory), and the liquid-phase reduction under this exchange current density can followingly be realized: as the type of conventional method selective reduction agent, and in the existence of the state of liquid phase, liquidus temperature, pH, additive whether or the like the concentration of the concentration of control reducing agent, the type that is used for providing the metallic compound of metal ion, metallic compound, metal ion.
A first aspect of the present invention is to make the method for metal dust, in the method, in liquid-phase reaction system, use the reducing agent reduction with precipitated metal ion, so that metal is with the form of metal powder granulates precipitation, wherein metal ion is reduced under the following conditions: the exchange current density of the redox reaction between metal ion and the reducing agent is 100 μ A/cm
2Or littler, exchange current density is determined by mixed potential theory.
A second aspect of the present invention is to make the method for metal dust according to first aspect, and wherein reducing agent is reduced sugar or sugar alcohol (glycitol).Because the reducing power of reduced sugar and sugar alcohol is low, so the electronics that reduced sugar and sugar alcohol can slow down in the process (4) effectively shifts.And, because having than higher molecular weight of other reducing agent and the resistance that causes because of liquid phase, reduced sugar and sugar alcohol make reduced sugar and sugar alcohol be not easy migration, therefore, reduced sugar and sugar alcohol can also slow down the mass transfer in process (3) and (5) effectively.Like this, reduced sugar and sugar alcohol can suppress nucleus growth, and are being excellent aspect the particle size that reduces metal dust.
Reduced sugar and sugar alcohol element free from foreign meter, for example halogen (for example chlorine), sulphur, phosphorus and boron; Therefore avoiding the distortion of metal dust and the nucleus growth of high speed, the distortion of metal dust is to be caused by the unusual nucleus growth that originates from these impurity elements.Therefore, according to a second aspect of the invention, can further reduce the particle size of metal dust.
A third aspect of the present invention is to make the method for metal dust according to first aspect, and wherein metal ion is reduced under the following conditions: carrier granular is dispersed in the liquid-phase reaction system, and metal powder granulates is deposited on the carrier particle surface thus.According to a third aspect of the invention we, can further reduce to have the noble metal powder particle size at platinum powder end for example in the catalyst of following structure: wherein the noble metal powder particle deposition and can reduce the consumption of noble metal when keeping high catalytic activity on carrier particle surface.
The example of carrier granular comprises carbon granule and inorganic compound particle.A fourth aspect of the present invention is to make the method for metal dust according to the third aspect, and wherein carrier granular is made by carbon or inorganic compound.
A fifth aspect of the present invention is to make the method for metal dust according to a first aspect of the invention, and reducing metal ion in liquid-phase reaction system wherein is so that metal powder granulates precipitates independently of one another.According to a fifth aspect of the invention, can further reduce the particle size of the noble metal powder made by gold, silver etc., to be applicable to the pigment of ink jet.Because the particle size distribution of metal dust can reduce by the nucleus growth of slowing down, therefore according to a fifth aspect of the invention, can also make noble metal powder with sharp particle size distribution.
Advantageous effects of the present invention
As mentioned above, the method according to this invention, can be used to implement the various factors (being reducing agent type and other factors) of liquid phase reduction and precipitate the metal dust of low particle size by reducing metal under the following conditions by control, described condition be that the exchange current density of the redox reaction between metal ion and the reducing agent is 100 μ A/cm
2Or littler (determining) by mixed potential theory.In other words, can be by in liquid-phase reaction system, using reducing agent reduction metal ion to be precipitated, thereby precipitation has the metal dust of low particle size, and described liquid-phase reaction system prepares by regulating metal ion, reducing agent and various if desired additive
And, under carrier granular is dispersed in situation in the reaction system, can make catalyst with following structure, promptly noble metal powder such as platinum is deposited on the carrier particle surface of being made by carbon or inorganic compound.When not having the dispersible carrier particle, in reaction system, implementing method of the present invention, can make the noble metal powders such as above-mentioned gold, silver of the pigment that is applicable to ink jet.
Description of drawings
Fig. 1 is the metallic compound measured when determining the exchange current density of redox reaction and the polarization curve of reducing agent.
The specific embodiment
The present invention is described below.
The method of＜measurement exchange current density 〉
By polarization measurement method, use three-electrode cell to measure the exchange current density of redox reaction with reference electrode, counterelectrode and working electrode.Reference electrode is silver/silver chloride electrode, and counterelectrode is a platinum electrode, and working electrode is made by the metal that is used to measure exchange current density (promptly with the metal that precipitated metal is identical).
By using above-mentioned three polarization of electrode mensurations, can measure the exchange current density under the predetermined condition in the following manner, described predetermined condition is used at specific reductant (being called reducing agent 1) with as the reaction of the combination of the special metal compound (being called metallic compound 1) of metal ion source.At first, preparation solution, this solution contain except that metallic compound 1 with the reaction system that is used to prepare metal dust (by liquid phase reduction, use reducing agent 1 and metallic compound 1) in identical component.Then, under the identical condition with the actual fabrication metal dust time (temperature has and stirs or do not have a stirring, etc.) three electrodes are immersed in the described solution.Then, apply voltage from rest potential (when immersing electrode, producing) towards positive direction scanning with constant sweep speed (1mV/sec usually) and draw the electric current variation simultaneously, to determine polarization curve (for example, the polarization curve La 1 among Fig. 1) at the reducing agent 1 of oxidation side.
Simultaneously, preparation contains solution identical with component in the reaction system except that reducing agent 1.Then, under the condition identical with the actual fabrication metal dust (temperature has stirring or does not have stirring, etc.) three electrodes are immersed in this solution.Then, apply voltage from rest potential (when immersing electrode, producing) towards negative direction scanning with constant sweep speed (1mV/sec usually) and draw the electric current variation simultaneously, to determine polarization curve (for example, the polarization curve Lc 1 among Fig. 1) at the metallic compound 1 of reduction side.
Can use the polarization curve La1 of above-mentioned definite reducing agent 1 and the polarization curve Lc of metallic compound 1
1, exchange current density (the μ A/cm of calculating redox reaction
2).More specifically, as shown in Figure 1, the voltage when determining oxidation current Ia (mA) and reduction current Ic (mA) balance, the voltage when promptly the absolute value of oxidation current Ia equals the absolute value of reduction current Ic, described voltage is limited by following general formula (1).
|Ia|＝|Ic| (1)
Then, with the absolute value (equaling the absolute value of reduction current Ic) of the oxidation current Ia under this voltage surface area (cm divided by working electrode
2).Like this, determine exchange current density (μ A/cm
2).
Curve La among Fig. 1
2And La
3Be the polarization curve of other reducing agent, it is to determine in the same manner as described above.With reference to the accompanying drawings, depress expression polarization curve La in same electrical
2The oxidation current of reducing agent (being called reducing agent 2) be lower than the oxidation current of reducing agent 1.Therefore, observe, the exchange current density of the redox reaction when reducing agent 2 metallizing things 1 use together can be less than the exchange current density of the redox reaction when reducing agent 1 metallizing thing 1 uses together.
And, depress expression polarization curve La in same electrical
3The oxidation current of reducing agent (being called reducing agent 3) be lower than the oxidation current of reducing agent 2.Therefore, the exchange current density of the redox reaction when reducing agent 3 metallizing things 1 use together can be further less than the exchange current density of the redox reaction when reducing agent 2 metallizing things 1 use together.This is the speed of carrying out because of differentia influence process (2)-(5) of the reducing power of reducing agent and molecular weight.Like this, confirmation can be controlled the exchange current density of redox reaction by the reducing agent of selecting the combination of metallizing thing.
The polarization curve difference of the polarization curve (not shown) metallizing thing 1 of the metallic compound except that metallic compound 1 (as metal ion source).This be because constitute the metal ion valence mumber of metallic compound difference, with metal ion constitute the difference of ionization potential of counter ion of metallic compound and counter ion size (atomic and formula weight) differentia influence process (2)-(5) carry out speed.Like this, confirmation can be controlled the exchange current density of redox reaction by the type that changes metallic compound.
In addition, for example can in liquid phase, form compound (complex) and come the stable metal ion that produces by metallic compound 1, thereby further reduce the speed of carrying out of said process (2)-(5) with other ion.Like this, can also control the exchange current density of redox reaction by adjusting the state of metal ion in liquid phase.
When making metal dust, even use identical reducing agent and identical metallic compound, polarization curve still changes with condition (temperature has and stirs or do not stir, etc.).Therefore, can control the exchange current density of redox reaction by adjusting above-mentioned condition.This is because the speed of carrying out of process (2)-(5) changes with reaction condition.
In the present invention, as mentioned above, by adjusting various conditions, the exchange current density of redox reaction is controlled to be 100 μ A/cm
2Or it is littler.Like this, the outstanding metal dust that can make very little particle size (and this can't be made by conventional method) and have sharp particle size distribution.
But,,, cause making the very long time of metal dust needs with predetermined particle size then because nucleus growth is too slow or the metal dust basis can not precipitate if exchange current density is too low.Therefore, consider the productivity ratio of metal dust, the exchange current density of redox reaction is preferably 1 μ A/cm
2Or the bigger value in the above-mentioned scope.
＜reducing agent 〉
Can use any known reducing agent, as long as, the exchange current density of redox reaction can be controlled at 100 μ A/cm by under appropriate condition, it being combined with suitable metallic compound
2Or littler getting final product.Especially, in order to reduce the particle size of metal dust, the preferred use has lower reducing power and the reducing agent of the middle electronics transfer of the process (4) that can slow down process.
The example of these reducing agents comprises as disclosed alcohol in the above-mentioned patent documentation for example methyl alcohol, ethanol, isopropyl alcohol, and ascorbic acid.Other example comprises ethylene glycol; Glutathione; Organic acid, for example citric acid, malic acid and tartaric acid; Reduced sugar, for example glucose, galactolipin, mannose, fructose, sucrose, maltose, gossypose, stachyose; With sugar alcohol D-sorbite for example.Especially, reduced sugar and derivative thereof for example sugar alcohol be preferred.
As mentioned above, because reduced sugar and sugar alcohol have low reducing power as reducing agent, so they are highly effective for the electron transfer rate in the reduction process (4).And, reduced sugar and the sugar alcohol mass transfer process in process (3) and (5) that can slow down because their molecular weight is greater than the molecular weight of other reducing agent, thereby they be subjected to from the resistance of liquid phase big, so their are difficult for migration.Like this, epoxy sugar and sugar alcohol are excellent reducing aspect the particle size of metal dust.
And, because reduced sugar and sugar alcohol element free from foreign meter for example halogen (for example chlorine), sulphur, phosphorus and boron, therefore can avoid owing to originate from the nucleus growth of the high speed that the unusual nucleus growth of these impurity elements causes and the distortion of metal dust.The example of most preferred reduced sugar and sugar alcohol comprises glucose, galactolipin, fructose, sucrose, maltose, gossypose, stachyose and the D-sorbite in the above-claimed cpd, and reason is that they are easily in industrial acquisition.
The concentration of the reducing agent in the liquid-phase reaction system is unrestricted.Usually, the trend of existence is that the exchange current density of redox reaction reduces with the reduction of reductant concentration, so the particle size of gained metal dust reduces.Therefore, consider the particle size of metal dust to be prepared, type and other condition of reducing agent, preferably determine the concentration range of reducing agent, thereby exchange current density is controlled to 100 μ A/cm
2Or it is littler.
＜metal ion source 〉
The metallic compound of the metal ion source of using as metal dust is selected from the various various metallic compounds that may be dissolved in the liquid phase and contain metal, so that described metallic compound can be controlled at 100 μ A/cm with the exchange current density of redox reaction with appropriate reductant under the condition of suitable adjustment
2Or it is littler.As mentioned above, if possible, preferable alloy compound element free from foreign meter, the miscellaneous affair element can become the source that causes unusual nucleus growth.But, can not stop metallic compound to contain under the situation of impurity element, can suppress unusual nucleus growth by selecting appropriate reductant and suitable other condition of adjusting, thereby preparation has the metal dust of low particle size.
Preferable alloy compound as metal ion source includes but not limited to, as dinitro diamino platinum (II) (Pt (NO in platinum ion source
2)
2(NH
3)
2) and chlordene platinum hydracid (IV) hexahydrate (H
2[PtCl
6] 6H
2O); Silver nitrate (I) (AgNO as source of silver ions
3) and methanesulfonic acid silver (CH
3SO
3Ag); Tetrachloro gold hydracid (III) tetrahydrate (HAuCl as the gold ion source
44H
2O); Palladium bichloride (II) (PdCl as the palladium ion source
2) solution; Chlordene iridium hydracid (III) hexahydrate (2 (IrCl as the iridium ion source
6) 6H
2O); Radium chloride (III) (RhCl as the rhodium ion source
33H
2O) solution; Nitric acid ruthenium (III) (Ru (NO as the ruthenium ion source
3)
3) solution.Especially, preferred dinitro diamino platinum (II) and silver nitrate (I).
＜additive 〉
The example of additive comprises the pH conditioning agent, is used to control the pH scope of liquid phase to be applicable to reduction and precipitation metal; Dispersant is used for the carrier granular of dispersed catalyst or the metal dust of load; And viscosity modifier, be used to control the viscosity of liquid phase.
Can use the various pH conditioning agents that comprise bronsted lowry acids and bases bronsted lowry.Especially, preferably do not contain the bronsted lowry acids and bases bronsted lowry that may become the impurity element that causes unusual nucleus growth source.The example of the pH conditioning agent of element free from foreign meter comprises as the nitric acid of acid with as the ammoniacal liquor of alkali.
The pH scope that is applicable to liquid phase depends on the type of precipitated metal with as the metallic compound of metal ion source.The trend that exists be the exchange current density of redox reaction in OK range with the reducing and reduce of pH, so the particle size of gained metal dust reduces.Therefore, consider type and other condition of the type of the metal dust that will make and particle size, reducing agent, by selecting whether to need the pH conditioning agent and if desired, the appropriate amount of the pH conditioning agent that will add is preferably determined to be applicable to exchange current density is controlled at 100 μ A/cm
2Or littler pH scope.
Can use any known dispersant and viscosity modifier.The preferred big dispersal agent molecule that uses with above-mentioned two kinds of functions.The example of big dispersal agent molecule comprises: the big dispersal agent molecule of amine, for example polyaziridine and polyvinylpyrrolidone; The big dispersal agent molecule of hydro carbons that has the carboxylic acid group in the molecule, for example carboxymethyl cellulose; The copolymer (being called the PEI-PO copolymer) that has polyaziridine part and PEO part in the molecule.
The amount of big dispersal agent molecule is unrestricted.But the viscosity of liquid phase raises with the increase of big dispersal agent molecule addition, and therefore, the exchange current density of redox reaction tends to reduce, and causes the particle size of gained metal dust to reduce.Therefore, consider the particle size of the metal dust that will make, type and other condition of reducing agent, preferably determine to be applicable to exchange current density is controlled at 100 μ A/cm
2Or the scope of the amount of littler big dispersal agent molecule.
The manufacturing of＜metal dust: 1 〉
When noble metal powders such as having platinum by the inventive method preparation is deposited on the catalyst of the structure on the carrier particle surface, prepare the liquid-phase reaction system of the metallic compound of the dispersible carrier particle, reducing agent and the predetermined concentration that contain scheduled volume according to conventional method.Then this liquid phase is placed under the condition of predetermined temperature,, thereby it is deposited on the carrier particle surface that is dispersed in the liquid phase with pulverulence with noble metals such as reduction platinum.Like this, can prepare catalyst with said structure.
In this process, temperature and viscosity that can be by regulator solution and the stirring condition (for example stir speed (S.S.)) when stirring are controlled the exchange current density of redox reaction.That is to say, the trend of existence be the exchange current density of redox reaction with the increase of the reduction of solution temperature, solution viscosity or when stirring the reduction of stir speed (S.S.) reduce, have the metal dust that particle size reduces thereby cause producing.Therefore, consider the particle size of the metal dust that will make, type and other condition of reducing agent, preferably determine to be applicable to exchange current density is controlled at 100 μ A/cm
2Or the scope of the amount of littler additive.Can be by being used in combination pure and mild other reducing agent reduces to be deposited on the metal dust on the carrier particle surface as reducing agent ratio.
The example of carrier granular comprises carbon granule and inorganic compound particle.Various types of carbon blacks can be used as carbon granule.The example of inorganic compound particle comprises: aluminium oxide, for example gama-alumina; Metal oxide, for example titanium dioxide, silica, cerium oxide, zirconia, ferrous oxide and mixed oxide thereof; Nitride metal composition granule, for example titanium nitride, nitrided iron and silicon nitride; And silver sulfide particle.
Depend on Application of Catalyst, the particle size of carrier granular is determined in any range.For example, with regard to specific area, the preferably about 50～500m of the particle size of inorganic compound particle
2/ g.To the processing that the catalyst that obtains like this carries out usual manner for example filter, wash, after the dry and activation, these catalyst can be used for fuel cell or waste gas purification.
The manufacturing of＜metal dust: 2 〉
When preparing the noble metal powders such as gold, silver of the above-mentioned pigment that is applicable to ink jet by the inventive method, contain the liquid phase of the reducing agent and the metallic compound of predetermined concentration according to the conventional method preparation.Then this liquid phase is placed under the condition of predetermined temperature, with noble metals such as reduction gold, silver, so that above-mentioned particle is deposited in the liquid phase with pulverulence separately.Like this, can prepare gold or silver powder.
In this case, temperature that also can be by regulator solution and viscosity and stirring condition for example have or not the stir speed (S.S.) when stirring and stirring, and control the exchange current density of redox reaction slightly.The trend that exists be the exchange current density of redox reaction with the increase of the reduction of solution temperature, solution viscosity or when stirring the reduction of stir speed (S.S.) reduce, thereby obtain having the metal dust that reduces particle size.Therefore, consider the particle size of the metal dust that will prepare, type and other condition of reducing agent, preferably determine to be applicable to exchange current density is controlled at 100 μ A/cm
2Or the scope of the amount of littler additive.
After carrying out carrying out washing treatment in the mode identical with conventional method, gold that obtains and silver powder are provided as the colloidal form that is dispersed in the decentralized medium (for example water or inorganic solvent), or filter, wash and dry the processing after be provided as powder type, to such an extent as to they can be used as, for example produce the pigment that ink jet or electrocondution slurry are used.
Like this, for example can use ink jet (wherein gold or silver powder are as conducting pigment) on printed substrate, to form electric wiring (electric wiring), perhaps can use ink jet (wherein gold or silver powder are as metallic pigments) to carry out operplate printing by ink-jet printer by ink-jet printer.And, for example can use electrocondution slurry to form the electric wiring of printed substrate by serigraphy, gold or silver powder are as conducting pigment in described electrocondution slurry.
Embodiment
Below with reference to embodiment the present invention is described.
＜platinum powder end and use platinum powder end preparation catalyst: I 〉
Embodiment 1
Prepare liquid-phase reaction system according to following steps: disperseing specific area in deionized water (300ml) is 800m
2/ g and surface p H are 9.2 carbon black support particle (2g), are sequentially added into dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L) with as the fructose of reducing agent, then, if desired, by adding nitric acid or ammoniacal liquor pH is adjusted to 1.5.The reaction system that obtains contains 0.02mol/L (M) platinum and 0.20M fructose.As for following 240 hours of 40 ℃ temperature conditions, use magnetic stirring apparatus under 400rpm, to stir simultaneously, this reaction system so that the platinum powder end is deposited in black carbon surface.Prepare catalyst like this.The exchange current density that records reaction system by said method is 4.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas.
The catalyst that isolated by filtration obtains also spends deionised water.After 8 hours, be deposited on the particle size at the platinum powder end of black carbon surface 50 ℃ of dryings according to following method measurement.That is to say, under the adsorption temp of 120 ℃ predetermined temperature and 50 ℃, handle the catalyst that obtains according to the CO absorption method, and the measure CO adsorbance.Calculate the surface area at the platinum powder end that is deposited on black carbon surface from measurement result.Measure the platinum amount that is deposited in the gained catalyst by inductively coupled plasma spectroscopic methodology (ICP).By this amount and surface area, the particle diameter that calculates the platinum powder end particle that is deposited on black carbon surface is 1.1nm.
Embodiment 2
As embodiment 1 preparation catalyst, difference is that the pH of reaction system is 5.0.The exchange current density of reaction system is 7.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle diameter that calculates the platinum powder end particle that is deposited on the carbon black is 1.9nm.
Embodiment 3
As embodiment 1 preparation catalyst, difference is that the pH of reaction system is 9.0.The exchange current density of reaction system is 10.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 2.5nm.
Embodiment 4
As embodiment 1 preparation catalyst, difference is that reaction temperature is 80 ℃.The exchange current density of reaction system is 25.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 7.5nm.
Embodiment 5
As embodiment 1 preparation catalyst, difference is that the concentration as the fructose of reducing agent is 0.10M.The exchange current density of reaction system is 3.5 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 0.9nm.
Embodiment 6
As embodiment 1 preparation catalyst, difference is that the concentration as the fructose of reducing agent is 0.40M.The exchange current density of reaction system is 9.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 2.3nm.
Embodiment 7
As embodiment 1 preparation catalyst, difference be amount by control dinitro diamino platinum (II) salpeter solution with the platinum concentration adjustment to 0.01M.The exchange current density of reaction system is 3.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 0.8nm.
Embodiment 8
As embodiment 1 preparation catalyst, difference be amount by control dinitro diamino platinum (II) salpeter solution with the platinum concentration adjustment to 0.04M.The exchange current density of reaction system is 11.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 2.7nm.
Embodiment 9
As embodiment 1 preparation catalyst, difference is to add big dispersal agent molecule polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000) as additive.The concentration of the polyvinylpyrrolidone in the reaction system is 1g/L.The exchange current density of reaction system is 3.9 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 1.0nm.
Embodiment 10
As embodiment 1 preparation catalyst, difference is that (product serial number No.1105:DAICEL CHEMICAL INDUSTRIES is LTD.) as additive for the big dispersal agent molecule carboxymethyl cellulose of adding.The concentration of the carboxymethyl cellulose in the reaction system is 1g/L.The exchange current density of reaction system is 3.9 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 1.0nm.
Embodiment 11
As embodiment 1 preparation catalyst, difference is that (the PAO306:NIPPON SHOKUBAI CO. of EPOMIN is LTD.) as additive for the big dispersal agent molecule PEI-PO copolymer of adding.The concentration of the PEI-PO copolymer in the reaction system is 1g/L.The exchange current density of reaction system is 3.9 μ A/cm
2The exchange current density of reaction system is 3.8 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 1.0nm.
Embodiment 12
As embodiment 1 preparation catalyst, difference is to add chlordene platinum hydracid (IV) hexahydrate rather than dinitro diamino platinum (II) salpeter solution.The concentration of the platinum in the reaction system is 0.02M.The exchange current density of reaction system is 23.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 6.5nm.
The result is as shown in table 1.Used symbol is as follows in the table:
The type of carrier granular
CB: carbon black
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
*2: chlordene platinum hydracid (IV) hexahydrate
The type of reducing agent
FL: fructose
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
*B: carboxymethyl cellulose (product serial number No.1105:DAICEL CHEMICALINDUSTRIES, LTD.)
*The c:PEI-PO copolymer (the PAO306:NIPPON SHOKUBAI CO. of EPOMIN , LTD.)
Table 1
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time and) | ||||
| Embodiment 1 | CB | *1 | 0.02 | FL | 0.20 | 40 | 1.5 | Do not have | 240 | ?4.0 | 1.1 |
| Embodiment 2 | CB | *1 | 0.02 | FL | 0.20 | 40 | 5.0 | Do not have | 240 | ?7.0 | 1.9 |
| Embodiment 3 | CB | *1 | 0.02 | FL | 0.20 | 40 | 9.0 | Do not have | 240 | ?10.0 | 2.5 |
| Embodiment 4 | CB | *1 | 0.02 | FL | 0.20 | 80 | 1.5 | Do not have | 240 | ?25.0 | 7.5 |
| Embodiment 5 | CB | *1 | 0.02 | FL | 0.10 | 40 | 1.5 | Do not have | 240 | ?3.5 | 0.9 |
| Embodiment 6 | CB | *1 | 0.02 | FL | 0.40 | 40 | 1.5 | Do not have | 240 | ?9.0 | 2.3 |
| Embodiment 7 | CB | *1 | 0.01 | FL | 0.20 | 40 | 1.5 | Do not have | 240 | ?3.0 | 0.8 |
| Embodiment 8 | CB | *1 | 0.04 | FL | 0.20 | 40 | 1.5 | Do not have | 240 | ?11.0 | 2.7 |
| Embodiment 9 | CB | *1 | 0.02 | FL | 0.20 | 40 | 1.5 | *a | 240 | ?3.9 | 1.0 |
| Embodiment 10 | CB | *1 | 0.02 | FL | 0.20 | 40 | 1.5 | *b | 240 | ?3.9 | 1.0 |
| Embodiment 11 | CB | *1 | 0.02 | FL | 0.20 | 40 | 1.5 | *c | 240 | ?3.8 | 1.0 |
| Embodiment 12 | CB | *2 | 0.02 | FL | 0.20 | 40 | 1.5 | Do not have | 240 | ?23.0 | 6.5 |
Observe by the embodiment result shown in the table, pH (embodiment 1-3) by reducing reaction system, by reduce reaction temperature (embodiment 1 and 4), by reducing reductant concentration (embodiment 1,5 and 6) or by reducing platinum concentration (embodiment 1,7 and 8), the exchange current density of redox reaction system can be reduced, and the particle size at platinum powder end can be reduced thus.
By found that of embodiment 1 and embodiment 9-11 in the table, the exchange current density that reduces the redox reaction system can reduce the particle size at platinum powder end, wherein can come increased viscosity, thereby reduce the exchange current density of redox reaction system by adding big dispersal agent molecule.And, by found that of embodiment 1 and 12,, also can change the exchange current density of redox reaction, thereby change the particle size at platinum powder end by the metallic compound of selecting to be used as the platinum ion source even other condition is identical.
Embodiment 13
As embodiment 1 preparation catalyst, difference is to use sucrose rather than fructose, and reaction temperature is 60 ℃.Sucrose concentration in the reaction system is 0.20M.The exchange current density of reaction system is 10.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 1.9nm.
Embodiment 14
As embodiment 1 preparation catalyst, difference is to use glucose rather than fructose, and reaction temperature is 60 ℃.Concentration of glucose in the reaction system is 0.20M.The exchange current density of reaction system is 48.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 5.2nm.
Embodiment 15
As embodiment 1 preparation catalyst, difference is to use galactolipin rather than fructose, and reaction temperature is 60 ℃.Galactose concentration in the reaction system is 0.20M.The exchange current density of reaction system is 16.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 4.3nm.
Embodiment 16
As embodiment 1 preparation catalyst, difference is to use citric acid rather than fructose, and reaction temperature is 60 ℃.Citric acid concentration in the reaction system is 0.20M.The exchange current density of reaction system is 30.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 16.0nm.
Embodiment 17
As embodiment 1 preparation catalyst, difference is to use ethylene glycol rather than fructose, and reaction temperature is 60 ℃.Glycol concentration in the reaction system is 900mL/L.The exchange current density of reaction system is 32.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 4.5nm.
Embodiment 18
As embodiment 1 preparation catalyst, difference is to use mannose rather than fructose, and reaction temperature is 60 ℃.Mannose concentration in the reaction system is 0.20M.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 1.9nm.
Embodiment 19
As embodiment 1 preparation catalyst, difference is to use ethanol rather than fructose, and reaction temperature is 60 ℃.Concentration of alcohol in the reaction system is 900mL/L.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 2.2nm.
Embodiment 20
As embodiment 1 preparation catalyst, difference is to use ascorbic acid rather than fructose, and reaction temperature is 20 ℃.The concentration of the ascorbic acid in the reaction system is 0.20M.The exchange current density of reaction system is 41.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 20.0nm.
Comparative example 1
As embodiment 20 preparation catalyst, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 700.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 90.0nm.
Embodiment 21
As embodiment 1 preparation catalyst, difference is to use malic acid rather than fructose, and reaction temperature is 20 ℃.The concentration of the malic acid in the reaction system is 0.20M.The exchange current density of reaction system is 1.5 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 4.8nm.
Embodiment 22
As embodiment 21 preparation catalyst, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 35.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 18.0nm.
Embodiment 23
As embodiment 1 preparation catalyst, difference is to use tartaric acid rather than fructose, and reaction temperature is 20 ℃.Tartaric concentration in the reaction system is 0.20M.The exchange current density of reaction system is 2.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 5.0nm.
Embodiment 24
As embodiment 23 preparation catalyst, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 40.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 22.0nm.
The result is as shown in table 2.The symbol that uses in the table is as follows:
The type of carrier granular
CB: carbon black
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
SC: sucrose
GL: glucose
GA: galactolipin
Ct: citric acid
EG: ethylene glycol
MN: mannose
Et: ethanol
As: ascorbic acid
Ma: malic acid
Ta: tartaric acid
Table 2
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Embodiment 13 | CB | *1 | 0.02 | SC | 0.20 | 60 | 1.5 | Do not have | 240 | ?10.0 | 1.9 |
| Embodiment 14 | CB | *1 | 0.02 | GL | 0.20 | 60 | 1.5 | Do not have | 240 | ?48.0 | 5.2 |
| Embodiment 15 | CB | *1 | 0.02 | GA | 0.20 | 60 | 1.5 | Do not have | 240 | ?16.0 | 4.3 |
| Embodiment 16 | CB | *1 | 0.02 | Ct | 0.20 | 60 | 1.5 | Do not have | 240 | ?30.0 | 16.0 |
| Embodiment 17 | CB | *1 | 0.02 | EG | 900mL/L | 60 | 1.5 | Do not have | 240 | ?32.0 | 4.5 |
| Embodiment 18 | CB | *1 | 0.02 | MN | 0.20 | 60 | 1.5 | Do not have | 240 | ?12.0 | 1.9 |
| Embodiment 19 | CB | *1 | 0.02 | Et | 900mL/L | 60 | 1.5 | Do not have | 240 | ?12.0 | 2.2 |
| Embodiment 20 | CB | *1 | 0.02 | As | 0.20 | 20 | 1.5 | Do not have | 240 | ?41.0 | 20.0 |
| Comparative example 1 | CB | *1 | 0.02 | As | 0.20 | 60 | 1.5 | Do not have | 240 | ?700.0 | 90.0 |
| Embodiment 21 | CB | *1 | 0.02 | Ma | 0.20 | 20 | 1.5 | Do not have | 240 | ?1.5 | 4.8 |
| Embodiment 22 | CB | *1 | 0.02 | Ma | 0.20 | 60 | 1.5 | Do not have | 240 | ?35.0 | 18.0 |
| Embodiment 23 | CB | *1 | 0.02 | Ta | 0.20 | 20 | 1.5 | Do not have | 240 | ?2.0 | 5.0 |
| Embodiment 24 | CB | *1 | 0.02 | Ta | 0.20 | 60 | 1.5 | Do not have | 240 | ?40.0 | 22.0 |
Found that by the embodiment shown in the table, even other condition is identical, also can change the exchange current density of redox reaction, thereby can change the particle size at platinum powder end by selective reduction agent from all cpds.By found that of embodiment 21-24 and comparative example 1, even reducing agent is identical, also by adjusting condition for example reaction temperature can change the exchange current density of redox reaction, can change the particle size at platinum powder end thus.Especially, result by embodiment 21 and comparative example 1 observes, even use conventional reduction agent (being ascorbic acid) (comparative example 1, corresponding to disclosed embodiment in the patent documentation 3), condition that also can be by adjusting reaction system is controlled at 100 μ A/cm with the exchange current density of redox reaction
2Or littler, thereby further reduce the particle size of metal dust.
Comparative example 2
As embodiment 1 preparation catalyst, difference is to use titanium trichloride rather than fructose, and reaction temperature is 20 ℃.Titanium trichloride concentration in the reaction system is 0.20M.The exchange current density of reaction system is 1800.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 180.0nm.
Comparative example 3
As comparative example 2 preparation catalyst, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 3800.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 280.0nm.
Comparative example 4
As embodiment 1 preparation catalyst, difference is to use sodium borohydride (NaBH
4) rather than fructose, and reaction temperature is 20 ℃.The concentration of the sodium borohydride in the reaction system is 0.20M.The exchange current density of reaction system is 5300.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 1200.0nm.
Comparative example 5
As comparative example 4 preparation catalyst, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 12000.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the carbon black is 2500.0nm.
The result is as shown in table 3.The symbol that uses in the table is as follows:
The type of carrier granular
CB: carbon black
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
TiCl
3: titanium trichloride
NaBH
4: sodium borohydride
Table 3
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Comparative example 2 | CB | *1 | 0.02 | TiCl 3 | 0.20 | 20 | 1.5 | Do not have | 240 | 1800.0 | 180.0 |
| Comparative example 3 | CB | *1 | 0.02 | TiCl 3 | 0.20 | 60 | 1.5 | Do not have | 240 | 3800.0 | 280.0 |
| Comparative example 4 | CB | *1 | 0.02 | NaBH 4 | 0.20 | 20 | 1.5 | Do not have | 240 | 5300.0 | 1200.0 |
| Comparative example 5 | CB | *1 | 0.02 | NaBH 4 | 0.20 | 60 | 1.5 | Do not have | 240 | 12000.0 | 2500.0 |
Found that by the comparative example shown in the table, when the reducing activity of reducing agent is too high,, also the exchange current density of redox reaction can't be controlled at 100 μ A/cm even adjust other condition
2Or littler, therefore can't reduce the particle size of metal dust.
＜platinum powder end and use platinum powder end preparation catalyst: II 〉
Embodiment 25
Prepare liquid-phase reaction system according to following steps: mixing the 12g specific area is 75m
2The gama-alumina particle of/g, 1g as carrier granular as the PEI-PO copolymer of big dispersal agent molecule (the PAO306:NIPPON SHOKUBAI CO. of EPOMIN , LTD.), the fructose as reducing agent, dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L) and deionized water; If desired, by adding nitric acid or NaOH pH is adjusted to 8.5; Adding deionized water then, to make cumulative volume be 1L.Platinum concentration in the reaction system is 0.2mM, and fructose concentration is 0.2M.
Prepare catalyst according to following steps: make this reaction system 80 ℃ of reactions 6 hours, use magnetic stirring apparatus under 400rpm, to stir simultaneously, the platinum powder end is deposited on the gama-alumina particle surface.The exchange current density that records reaction system by said method is 12.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 0.3mPas.Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.
Embodiment 26
As embodiment 25 preparation catalyst, difference is to use 1g CELUNAD-735 (CHUKYO YUSHI CO., the trade name of LTD.) rather than PEI-PO copolymer as big dispersal agent molecule.The exchange current density of reaction system is 15.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3.0nm.
Embodiment 27
As embodiment 25 preparation catalyst, difference be to use 1g alkene-maleate copolymer (Polyster OMA : NOF CORPORATION, weight average molecular weight (Mw): about 10000) rather than the PEI-PO copolymer as big dispersal agent molecule.The exchange current density of reaction system is 18.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3.5nm.
Embodiment 28
As embodiment 25 preparation catalyst, difference be to use the 1g polyacrylic acid (weight average molecular weight (Mw): 5000) rather than the PEI-PO copolymer as big dispersal agent molecule.The exchange current density of reaction system is 25.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 5.0nm.
Embodiment 29
As embodiment 25 preparation catalyst, difference is to use 1g polyvinylpyrrolidone (TOKYOKASEI KOGYO CO., LTD., molecular weight: 10000) rather than the PEI-PO copolymer as big dispersal agent molecule, and use glucose rather than fructose as reducing agent.The concentration of the glucose in the reaction system is 0.2M.The exchange current density of reaction system is 13.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.5nm.
Embodiment 30
As embodiment 29 preparation catalyst, difference is to use galactolipin rather than glucose.The concentration of the galactolipin in the reaction system is 0.2M.The exchange current density of reaction system is 13.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.6nm.
Embodiment 31
As embodiment 29 preparation catalyst, difference is to use sucrose rather than glucose.Concentration of sucrose in the reaction system is 0.2M.The exchange current density of reaction system is 14.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.8nm.
Embodiment 32
As embodiment 29 preparation catalyst, difference is to use citric acid rather than glucose.The concentration of the citric acid in the reaction system is 0.2M.The exchange current density of reaction system is 30.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 16nm.
Embodiment 33
As embodiment 29 preparation catalyst, difference is to use ethylene glycol rather than glucose.The concentration of the ethylene glycol in the reaction system is 200mL/L.The exchange current density of reaction system is 20.0 μ A/cm
2Under this temperature, the viscosity of reaction system is 13mPaS.Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3.5nm.
Embodiment 34
As embodiment 29 preparation catalyst, difference is to use mannose rather than glucose.The concentration of the mannose in the reaction system is 0.2M.The exchange current density of reaction system is 19.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3.3nm.
Embodiment 35
As embodiment 29 preparation catalyst, difference is to use ethanol rather than glucose.Concentration of ethanol in the reaction system is 200mL/L.The exchange current density of reaction system is 24.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 0.25mPas.Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 4.5nm.
Embodiment 36
As embodiment 29 preparation catalyst, difference is to use malic acid rather than glucose.The concentration of the malic acid in the reaction system is 0.2M.The exchange current density of reaction system is 35.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 18nm.
Embodiment 37
As embodiment 29 preparation catalyst, difference is to use tartaric acid rather than glucose.Tartaric concentration in the reaction system is 0.2M.The exchange current density of reaction system is 40.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 22nm.
The result is as shown in table 4.The symbol that uses in the table is as follows:
The type of carrier granular
Al
2O
3: the gama-alumina particle
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
FL: fructose
GL: glucose
GA: galactolipin
SC: sucrose
Ct: citric acid
EG: ethylene glycol
MN: mannose
Et: ethanol
Ma: malic acid
Ta: tartaric acid
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
*The c:PEI-PO copolymer (the PAO306:NIPPON SHOKUBAI CO. of EPOMIN , LTD.)
*E:CELUNA D-735 (CHUKYO YUSHI CO., the trade name of LTD.)
*F: alkene-maleate copolymer (Polyster OMA : NOF CORPORATION, weight average molecular weight (Mw): about 10000)
*G: polyacrylic acid (weight average molecular weight (Mw): 5000)
Table 4
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Embodiment 25 | Al2O3 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *c | 6 | 12.0 | 2.4 |
| Embodiment 26 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *e | 6 | 15.0 | 3.0 |
| Embodiment 27 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *f | 6 | 18.0 | 3.5 |
| Embodiment 28 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *g | 6 | 25.0 | 5.0 |
| Embodiment 29 | Al 2O 3 | *1 | 0.2 | GL | 0.20 | 80 | 8.5 | *a | 6 | 13.0 | 2.5 |
| Embodiment 30 | Al 2O 3 | *1 | 0.2 | GA | 0.20 | 80 | 8.5 | *a | 6 | 13.0 | 2.6 |
| Embodiment 31 | Al 2O 3 | *1 | 0.2 | SC | 0.20 | 80 | 8.5 | *a | 6 | 14.0 | 2.8 |
| Embodiment 32 | Al 2O 3 | *1 | 0.2 | Ct | 0.20 | 80 | 8.5 | *a | 6 | 30.0 | 16.0 |
| Embodiment 33 | Al 2O 3 | *1 | 0.2 | EG | 200mL/L | 80 | 8.5 | *a | 6 | 20.0 | 3.5 |
| Embodiment 34 | Al 2O 3 | *1 | 0.2 | MN | 0.20 | 80 | 8.5 | *a | 6 | 19.0 | 3.3 |
| Embodiment 35 | Al 2O 3 | *1 | 0.2 | Et | 200mL/L | 80 | 8.5 | *a | 6 | 24.0 | 4.5 |
| Embodiment 36 | Al 2O 3 | *1 | 0.2 | Ma | 0.20 | 80 | 8.5 | *a | 6 | 35.0 | 18.0 |
| Embodiment 37 | Al 2O 3 | *1 | 0.2 | Ta | 0.20 | 80 | 8.5 | *a | 6 | 40.0 | 22.0 |
By found that of embodiment shown in the table, as the situation of using carbon black as carrier granular, the platinum powder end can also be deposited on the gama-alumina particle surface as carrier granular.By found that of embodiment 25-37, can be by the exchange current density of selecting to control redox reaction as the big dispersal agent molecule or the selective reduction agent of additive, and control the particle size at platinum powder end thus.
Embodiment 38
As embodiment 29 preparation catalyst, it is 150m that difference is to use the 12g specific area
2The gama-alumina particle of/g (SUMITOMO CHEMICAL INDUSTRIES INC.) is as carrier granular and use fructose rather than glucose.Fructose concentration in the reaction system is 0.2M.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.
Embodiment 39
As embodiment 38 preparation catalyst, it is 250m that difference is to use the 12g specific area
2The gama-alumina particle of/g (ALCAN INC.) is as carrier granular.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.
Embodiment 40
As embodiment 38 preparation catalyst, it is 100m that difference is to use the 12g specific area
2The titanium dioxide granule of/g (Anatase:TITAN KOGYO KABUSHIKI KAISYA) is as carrier granular.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.4nm.
Embodiment 41
As embodiment 38 preparation catalyst, it is 500m that difference is to use the 12g specific area
2(KANTO KAGAKU CO. is LTD.) as carrier granular for the silica dioxide granule of/g.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.4nm.
Embodiment 42
As embodiment 38 preparation catalyst, it is 165m that difference is to use the 12g specific area
2(SHIN-ETSU CHEMICAL CO. is LTD.) as carrier granular for the cerium oxide particle of/g.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.4nm.
Embodiment 43
As embodiment 38 preparation catalyst, it is 75m that difference is to use the 12g specific area
2(KANTO KAGAKU CO. is LTD.) as carrier granular for the zirconia particles of/g.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.4nm.
Embodiment 44
As embodiment 38 preparation catalyst, it is 100m that difference is to use the 12g specific area
2The cerium of/g-Zr mixed oxide particle (Ce: Zr=1: 1, solid solution) as carrier granular.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.4nm.
The result is as shown in table 5.The symbol that uses in the table is as follows:
The type of carrier granular
Al
2O
3: the gama-alumina particle
TiO
2: titanium dioxide granule
SiO
2: silica dioxide granule
CeO
2: cerium oxide particle
ZrO
2: zirconia particles
CeZrO: cerium-Zr mixed oxide particle
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
FL: fructose
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
Table 5
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | |||||||
| Type | Specific area | Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | |||
| Embodiment 38 | Al 2O 3 | 150 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 39 | A1 2O 3 | 250 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 40 | TiO 2 | 100 | *1 | 02 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 41 | SiO 2 | 500 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 42 | CeO 2 | 165 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 43 | ZrO 2 | 75 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 44 | CeZrO | 100 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 12.0 | 2.4 |
Be can be observed by the embodiment result shown in the table, the platinum powder end can also be deposited on the various metal oxide surfaces as carrier granular.
Embodiment 45
As embodiment 29 preparation catalyst, difference is to use fructose rather than glucose, and the pH of reaction system is 7.0.Fructose concentration in the reaction system is 0.2M.The exchange current density of reaction system is 23.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 5.3nm.
Embodiment 46
As embodiment 45 preparation catalyst, difference is that the pH of reaction system is 8.0.The exchange current density of reaction system is 21.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 4.5nm.
Embodiment 47
As embodiment 45 preparation catalyst, difference is that the pH of reaction system is 9.0.The exchange current density of reaction system is 13.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.
Embodiment 48
As embodiment 45 preparation catalyst, difference is that the pH of reaction system is 9.5.The exchange current density of reaction system is 15.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.7nm.
Embodiment 49
As embodiment 45 preparation catalyst, difference is that the pH of reaction system is 10.0.The exchange current density of reaction system is 19.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3.3nm.
Embodiment 50
As embodiment 29 preparation catalyst, difference is to use fructose rather than glucose, and reaction temperature is 50 ℃.Fructose concentration in the reaction system is 0.2M.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.3nm.
Embodiment 51
As embodiment 50 preparation catalyst, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.
Embodiment 52
As embodiment 50 preparation catalyst, difference is that reaction temperature is 70 ℃.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.
Embodiment 53
As embodiment 50 preparation catalyst, difference is that reaction temperature is 90 ℃.The exchange current density of reaction system is 13.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.5nm.
Embodiment 54
As embodiment 29 preparation catalyst, difference is to use fructose rather than glucose, and uses chlordene platinum hydracid (IV) hexahydrate (H
2[PtCl
6] 6H
2O) rather than dinitro diamino platinum (II) salpeter solution.Platinum concentration in the reaction system is 0.2mM.Fructose concentration in the reaction system is 0.2M.The exchange current density of reaction system is 22.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3.8nm.
The result is as shown in table 6.The symbol that uses in the table is as follows:
The type of carrier granular
Al
2O
3: the gama-alumina particle
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
*2: chlordene platinum hydracid (IV) hexahydrate
The type of reducing agent
FL: fructose
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
Table 6
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (mm) | ||||||
| Type | Concentration (mM) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Embodiment 45 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 7.0 | *a | 6 | 23.0 | 5.3 |
| Embodiment 46 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 8.0 | *a | 6 | 21.0 | 4.5 |
| Embodiment 47 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 9.0 | *a | 6 | 13.0 | 2.4 |
| Embodiment 48 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 9.5 | *a | 6 | 15.0 | 2.7 |
| Embodiment 49 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 80 | 10.0 | *a | 6 | 19.0 | 3.3 |
| Embodiment 50 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 50 | 8.5 | *a | 6 | 12.0 | 2.3 |
| Embodiment 51 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 60 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 52 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 70 | 8.5 | *a | 6 | 12.0 | 2.4 |
| Embodiment 53 | Al 2O 3 | *1 | 0.2 | FL | 0.20 | 90 | 8.5 | *a | 6 | 13.0 | 2.5 |
| Embodiment 54 | Al 2O 3 | *2 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | 22.0 | 3.8 |
Result and the embodiment 25 of front and found that of front 38-43 by embodiment 45-49 are adjusted between the 8.5-9.5 by the pH with reaction system, can reduce the exchange current density of redox reaction, and reduce the particle size at platinum powder end thus.By the result of embodiment 50-53 and found that of front embodiment 25 and 38-43, can reduce the exchange current density of redox reaction by reducing reaction temperature, and reduce the particle size at platinum powder end thus.By the result of embodiment 54 and found that of embodiment 25 and 38-43, can reduce the exchange current density of redox reaction as metallic compound by using dinitro diamino platinum (II) salpeter solution, and reduce the particle size at platinum powder end thus.
Embodiment 55
Prepare liquid-phase reaction system according to following steps: mixing the 12g specific area is 75m
2Polyvinylpyrrolidone (the TOKYO KASEI KOGYO CO. of the gama-alumina particle of/g, the big dispersal agent molecule of 1g conduct as carrier granular, 10000), LTD., molecular weight: as the fructose of reducing agent and ethanol, dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L) and deionized water; If desired, by adding nitric acid or NaOH pH is adjusted to 8.5; Adding deionized water then, to make cumulative volume be 1L.Platinum concentration in the reaction system is 0.2mM, and fructose concentration is 0.2M, and concentration of alcohol is 200mL/L.
Prepare catalyst according to following steps: make this reaction system 80 ℃ of reactions 6 hours, use magnetic stirring apparatus under 400rpm, to stir simultaneously, the platinum powder end is deposited on the gama-alumina particle surface.The exchange current density that records reaction system by said method is 12.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 0.3mPas.Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.Measure the amount of the load platinum of gained catalyst by inductively coupled plasma spectroscopic methodology (ICP), by the platinum concentration in this amount and the reaction system, the ratio that calculates the platinum powder end that is deposited on carrier particle surface is 97.5 moles of %.
Embodiment 56
As embodiment 55 preparation catalyst, difference is that concentration of alcohol is 100mL/L.The exchange current density of reaction system is 12.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.4nm.The ratio at load platinum powder end is 84.3 moles of %.
Embodiment 57
As embodiment 55 preparation catalyst, difference is only to use fructose not use ethanol as reducing agent.The exchange current density of reaction system is 13.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.6nm.The ratio at load platinum powder end is 55.2 moles of %.
Embodiment 58
As embodiment 55 preparation catalyst, difference is to use methyl alcohol rather than ethanol.Methanol concentration in the reaction system is 200mL/L.The exchange current density of reaction system is 11.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.3nm.The ratio at load platinum powder end is 98.5 moles of %.
Embodiment 59
As embodiment 55 preparation catalyst, difference is to use isopropyl alcohol rather than ethanol.Isopropyl alcohol concentration in the reaction system is 200mL/L.The exchange current density of reaction system is 16.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.7nm.The ratio at load platinum powder end is 99.9 moles of %.
The result is as shown in table 7.The symbol that uses in the table is as follows:
The type of carrier granular
Al
2O
3: the gama-alumina particle
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
FL: fructose
Et: ethanol
Me: methyl alcohol
IPr: isopropyl alcohol
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
Table 7
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | The ratio (mol%) at load platinum powder end | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | |||||
| Embodiment 55 | Al 2O 3 | *1 | ?0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?12.0 | 2.4 | 97.5 |
| Et | 200mL/L | |||||||||||
| Embodiment 56 | Al 2O 3 | *1 | ?0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?12.0 | 2.4 | 84.3 |
| Et | 200mL/L | |||||||||||
| Embodiment 57 | Al 2O 3 | *1 | ?0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?13.0 | 2.6 | 55.2 |
| Et | - | |||||||||||
| Embodiment 58 | Al 2O 3 | *1 | ?0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?11.0 | 2.3 | 98.5 |
| Me | 200mL/L | |||||||||||
| Embodiment 59 | Al 2O 3 | *1 | ?0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?16.0 | 2.7 | 99.9 |
| iPr | 200mL/L | |||||||||||
Observe by the embodiment result in the table,, can keep the very platinum powder end of low particle size simultaneously by using the combination of pure and mild other reducing agent, can improve the ratio at the platinum powder end that is deposited on carrier particle surface.
Embodiment 60
Prepare liquid-phase reaction system according to following steps: mixing the 60g specific area is 10m
2Polyvinylpyrrolidone (the TOKYO KASEI KOGYO CO. of the titanium nitride of/g (TiN) particle, the big dispersal agent molecule of 1g conduct as carrier granular, 10000), the fructose as reducing agent, dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L) and deionized water LTD., molecular weight:; If desired, by adding nitric acid or NaOH pH is adjusted to 8.5; Adding deionized water then, to make cumulative volume be 1L.Platinum concentration in the reaction system is 0.2mM, and fructose concentration is 0.2M, and concentration of alcohol is 200mL/L.
Prepare catalyst according to following steps: reaction system was reacted 6 hours down for 80 ℃, use magnetic stirring apparatus under 400rpm, to stir simultaneously, so that on the titanium nitride particles surface, precipitate the platinum powder end.The exchange current density that records reaction system by said method is 15.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 0.3mPas.Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 2.8nm.
Embodiment 61
As embodiment 60 preparation catalyst, it is 10m that difference is to use the 60g specific area
2Silicon nitride (the Si of/g
3N
4) particle is as carrier granular.The exchange current density of reaction system is 15.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.8nm.
Embodiment 62
As embodiment 60 preparation catalyst, it is 10m that difference is to use the 60g specific area
2Silver sulfide (the Ag of/g
2S) particle is as carrier granular.The exchange current density of reaction system is 15.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the titanium dioxide granule is 2.8nm.
The result is as shown in table 8.The symbol that uses in the table is as follows:
The type of carrier granular
TiN: titanium nitride particles
Si
3N
4: silicon nitride particle
Ag
2S: silver sulfide particle
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
FL: fructose
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
Table 8
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Embodiment 60 | TiN | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?15.0 | 2.8 |
| Embodiment 61 | Si 3N 4 | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?15.0 | 2.8 |
| Embodiment 62 | Ag 2S | *1 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?15.0 | 2.8 |
Found that by the embodiment in the table platinum powder end can also be deposited on the various metallic compounds surface as carrier granular.
Comparative example 6
As embodiment 29 preparation catalyst, difference is to use ascorbic acid rather than glucose.Ascorbic acid concentrations in the reaction system is 0.2M.The exchange current density of reaction system is 800.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 30.5nm.
Comparative example 7
As embodiment 29 preparation catalyst, difference is to use titanium trichloride rather than glucose.Titanium trichloride concentration in the reaction system is 0.2M.The exchange current density of reaction system is 2400.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 150.0nm.
Comparative example 8
As embodiment 29 preparation catalyst, difference is to use sodium hypophosphite (NaH
2PO
2H
2O) rather than glucose.Sodium hypophosphite concentration in the reaction system is 0.2M.The exchange current density of reaction system is 7200.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 1500.0nm.
Comparative example 9
As embodiment 29 preparation catalyst, difference is to use sodium borohydride (NaBH
4) rather than glucose.Sodium borohydride concentration in the reaction system is 0.2M.The exchange current density of reaction system is 15000.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the platinum powder end that is deposited on the gama-alumina particle is 3000.0nm.
The result is as shown in table 9.The symbol that uses in the table is as follows:
The type of carrier granular
Al
2O
3: the gama-alumina particle
The type of metallic compound
*1: dinitro diamino platinum (II) salpeter solution (platinum concentration: 50g/L)
The type of reducing agent
As: ascorbic acid
TiCl
4: titanium trichloride
NaH
2PO
2: sodium hypophosphite
NaBH
4: sodium borohydride
Table 9
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Comparative example 6 | Al 2O 3 | *1 | 0.2 | As | 0.20 | 80 | 8.5 | *a | 6 | 800.0 | 30.5 |
| Comparative example 7 | Al 2O 3 | *1 | 0.2 | TiCl 3 | 0.20 | 80 | 8.5 | *a | 6 | 2400.0 | 150.0 |
| Comparative example 8 | Al 2O 3 | *1 | 0.2 | NaH 2PO 2 | 0.20 | 80 | 8.5 | *a | 6 | 7200.0 | 1500.0 |
| Comparative example 9 | Al 2O 3 | *1 | 0.2 | NaBH 4 | 0.20 | 80 | 8.5 | *a | 6 | 15000.0 | 3000.0 |
Found that by the comparative example shown in the table, when the reducing activity of reducing agent is too high,, also the exchange current density of redox reaction can't be controlled at 100 μ A/cm even regulate other condition
2Or littler, therefore can't reduce the particle size of metal dust.
＜various types of platinums group metal powder and use its preparation catalyst
Embodiment 63
Prepare liquid-phase reaction system according to following steps: mixing the 12g specific area is 75m
210000), the fructose as reducing agent, palladium bichloride (II) (PdCl the gama-alumina particle as carrier granular of/g, 1g are as the polyvinylpyrrolidone of big dispersal agent molecule (TOKYO KASEI KOGYO CO., LTD., molecular weight:
2) solution and deionized water; If desired, by adding nitric acid or NaOH pH is adjusted to 8.5; Adding deionized water then, to make cumulative volume be 1L.Palladium concentration in the reaction system is 0.2mM, and fructose concentration is 0.2M.
Prepare catalyst according to following steps: reaction system was reacted 6 hours down at 80 ℃, use magnetic stirring apparatus under 400rpm, to stir simultaneously, so that the palladium powder deposition is on the gama-alumina particle.The exchange current density that records reaction system by said method is 21.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 0.3mPas.Press embodiment 1 and handle after the gained catalyst, calculate the palladium particles of powder that is deposited on the gama-alumina particle and be of a size of 3.3nm.
Embodiment 64
As embodiment 63 preparation catalyst, difference is to use chlordene iridium hydrohalogenic acid salt (III) hexahydrate (2 (IrCl
6) 6H
2O) rather than palladium bichloride (II) solution.Iridium concentration in the reaction system is 0.2mM.The exchange current density of reaction system is 23.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the iridium powder particle that is deposited on the gama-alumina particle is 3.5nm.
Embodiment 65
As embodiment 63 preparation catalyst, difference is to use radium chloride (III) (RhCl
33H
2O) solution rather than palladium bichloride (II) solution.Rhodium concentration in the reaction system is 0.2mM.The exchange current density of reaction system is 21.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, the particle size that calculates the rhodium dust particle that is deposited on the gama-alumina particle is 3.3nm.
Embodiment 66
As embodiment 63 preparation catalyst, difference is to use nitric acid ruthenium (Ru (NO
3)
3) solution rather than palladium bichloride (II) solution.Ruthenium concentration in the reaction system is 0.2mM.The exchange current density of reaction system is 22.0 μ A/cm
2Press embodiment 1 and handle after the gained catalyst, calculating the particle size that is deposited in the rhodium dust on the gama-alumina particle is 3.2nm.
The result is as shown in table 10.The symbol that uses in the table is as follows:
The type of carrier granular
Al
2O
3: the gama-alumina particle
The type of metallic compound
*3: palladium bichloride (II) solution
*4: chlordene iridium hydracid (III) hexahydrate
*5: radium chloride (III) solution
*6: nitric acid ruthenium (III) solution
The type of reducing agent
FL: fructose
The type of additive
*A: polyvinylpyrrolidone (TOKYO KASEI KOGYO CO., LTD., molecular weight: 10000)
Table 10
| Carrier granular | Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at platinum powder end (nm) | ||||||
| Type | Concentration (M) | Type | Concentration (M) | Reaction temperature (℃) | pH | Additive | Reaction time (hr) | ||||
| Embodiment 63 | Al 2O 3 | *3 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?21.0 | 3.3 |
| Embodiment 64 | Al 2O 3 | *4 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?23.0 | 3.5 |
| Embodiment 65 | Al 2O 3 | *5 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?21.0 | 3.3 |
| Embodiment 66 | Al 2O 3 | *6 | 0.2 | FL | 0.20 | 80 | 8.5 | *a | 6 | ?22.0 | 3.2 |
Found that by the embodiment shown in the table the same with the situation of using the platinum powder end, various types of platinums group metal powder also can be deposited on the carrier particle surface.
＜preparation silver powder 〉
Embodiment 67
Prepare the silver nitrate ammonia spirit according to following steps: silver nitrate is dissolved in the deionized water, to wherein adding ammoniacal liquor pH is adjusted to 11 then.Will as the polyvinylpyrrolidone of big dispersal agent molecule (the K30 level: WAKO PURE CHEMICAL IND., LTD.) be dissolved in fully in the silver nitrate ammonia spirit, add then by being dissolved in the solution for preparing in the deionized water as the fructose of reducing agent.Prepare liquid-phase reaction system like this.Silver concentration in the reaction system is 26g/L, and fructose concentration is 50g/L, and the concentration of polyvinylpyrrolidone is 10g/L.
Then, reacted 3 hours under 10 ℃ reaction temperature by making described reaction system, use magnetic stirring apparatus to stir under 1000rpm simultaneously, preparation shows the yellow colloidal silver solution that plasmon absorbs (plasmonadsorption), with the precipitated silver powder.The exchange current density that records reaction system by said method is 2.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.
The colloidal silver solution of centrifugal gained reaches 20 minutes repeatedly under 20000G, to remove the impurity lighter than silver powder particle.Spend the deionised water silver powder then.Use laser Doppler method (laserDoppler method), adopt particle size distribution analysis instrument (the UPA150EX:NIKKISO CO. of product serial number No.Microtrac, LTD.) measure, the result observes at the 5nm place and occurs sharp peak (sharp peak) in the particle size distribution.
Embodiment 68
As embodiment 67 preparation colloidal silver solutions, difference is that reaction temperature is 30 ℃.The exchange current density of reaction system is 2.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 15nm place.
Embodiment 69
As embodiment 67 preparation colloidal silver solutions, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 20.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 25nm place.
Embodiment 70
As embodiment 67 preparation colloidal silver solutions, difference is that the silver nitrate concentration in the reaction system is 5.2g/L, and the concentration that is used as the fructose of reducing agent in the reaction system is 10g/L, and reaction temperature is 60 ℃.The exchange current density of reaction system is 18.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 25nm place.
Embodiment 71
As embodiment 67 preparation colloidal silver solutions, difference is that the pH of silver nitrate ammonia spirit is 12, and reaction temperature is 60 ℃.The exchange current density of reaction system is 40.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.5.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 40nm place.
Embodiment 72
As embodiment 67 preparation colloidal silver solutions, difference is to use methanesulfonic acid silver rather than silver nitrate, and reaction temperature is 60 ℃.Silver concentration in the reaction system is 26g/L.The exchange current density of reaction system is 75.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 3.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 30nm place.
Comparative example 10
As embodiment 67 preparation colloidal silver solutions, difference is to omit to add ammoniacal liquor (pH of solution is 6.5) after silver nitrate being dissolved in the deionized water, and reaction temperature is 60 ℃.The exchange current density of reaction system is 120.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 7.5.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 250nm place.
Embodiment 73
As embodiment 67 preparation colloidal silver solutions, difference is to use ascorbic acid rather than fructose, and reaction temperature is 5 ℃, and the reaction time is 0.5 hour.The concentration of the ascorbic acid in the reaction system is 26g/L.The exchange current density of reaction system is 70.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 35nm place.
Embodiment 74
As embodiment 73 preparation colloidal silver solutions, difference is that reaction temperature is 30 ℃.The exchange current density of reaction system is 90.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 40nm place.
Comparative example 11
As embodiment 73 preparation colloidal silver solutions, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 240.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 80nm place.
The result is as shown in table 11.Used symbol is as follows in the table:
The type of metallic compound
AgNO
3: silver nitrate
MS-Ag: methanesulfonic acid silver
The type of reducing agent
FL: fructose
As: ascorbic acid
The type of additive
NH
3: ammoniacal liquor
*D: polyvinylpyrrolidone (the K30 level: WAKO PURE CHEMICAL IND., LTD.)
pH
#1: the pH of silver nitrate ammonia spirit
#2: the pH of whole reaction system
Table 11
| Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size of silver powder (nm) | |||||||||
| Type | Concentration (g/L) | Type | Concentration (g/L) | Reaction temperature (℃) | Additive | pH (#1) | pH (#2) | Viscosity (mPas) | Reaction time (hr) | ||||
| Embodiment 67 | AgNO 3 | 26 | FL | 50 | 10 | NH 3 | *d | 11 | 8 | 1 | 3 | 2.0 | 5 |
| Embodiment 68 | AgNO 3 | 26 | FL | 50 | 30 | NH 3 | *d | 11 | 8 | 1 | 3 | 2.0(？) | 15 |
| Embodiment 69 | AgNO 3 | 26 | FL | 50 | 60 | NH 3 | *d | 11 | 8 | 1 | 3 | 20.0 | 25 |
| Embodiment 70 | AgNO 3 | 5.2 | FL | 10 | 60 | NH 3 | *d | 11 | 8 | 1 | 3 | 18.0 | 25 |
| Embodiment 71 | AgNO 3 | 26 | FL | 50 | 60 | NH 3 | *d | 12 | 8.5 | 1 | 3 | 40.0 | 40 |
| Embodiment 72 | MS-Ag | 26 | FL | 50 | 60 | NH 3 | *d | 11 | 3 | 1 | 3 | 75.0 | 30 |
| Comparative example 10 | AgNO 3 | 26 | FL | 50 | 60 | Do not have | *d | 6.5 | 7.5 | 1 | 3 | 120.0 | 250 |
| Embodiment 73 | AgNO 3 | 26 | As | 26 | 5 | NH 3 | *d | 11 | 8 | 1 | 0.5 | 70.0 | 35 |
| Embodiment 74 | AgNO 3 | 26 | As | 26 | 30 | NH 3 | *d | 11 | 8 | 1 | 0.5 | 90.0 | 40 |
| Comparative example 11 | AgNO 3 | 26 | As | 26 | 60 | NH 3 | *d | 11 | 8 | 1 | 0.5 | 240.0 | 80 |
Found that by the embodiment shown in the table, can be by reducing reaction temperature (embodiment 67-69, embodiment 73 and 74, and comparative example 11) or the pH (embodiment 67 and 71) that reduces reaction system reduce the exchange current density of redox reaction, can reduce the particle size of silver powder thus.By found that of embodiment 69 and 70, when platinum concentration and reductant concentration all reduce, the particle size at redox exchange current density and platinum powder end can be remained on essentially identical level,
By found that of embodiment 67 and comparative example 10, the situation that is in exposed state with silver ion is compared, stablizing under the situation of the silver ion in the liquid phase by forming compound with ammoniacal liquor, can reduce the exchange current density of redox reaction, can reduce the particle size of silver powder thus.
And, by found that of embodiment 67 and 72,, can change the exchange current density of redox reaction as source of silver ions by selecting different compounds even other condition is identical, can change the particle size of silver powder thus.
Embodiment 75
As embodiment 67 preparation colloidal silver solutions, difference is to use mannose rather than fructose, and reaction temperature is 60 ℃, and the reaction time is 1 hour.Mannose concentration in the reaction system is 50g/L.The exchange current density of reaction system is 15.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 8nm place.
Embodiment 76
As embodiment 67 preparation colloidal silver solutions, difference is to use ethanol rather than fructose, and reaction temperature is 30 ℃.Concentration of alcohol in the reaction system is 5g/L.The exchange current density of reaction system is 20.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 35nm place.
Embodiment 76
As embodiment 67 preparation colloidal silver solutions, difference is to use malic acid rather than fructose, and reaction temperature is 25 ℃, and the reaction time is 1.5 hours.Malic acid concentration in the reaction system is 13g/L.The exchange current density of reaction system is 95.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 28nm place.
Comparative example 12
As embodiment 77 preparation colloidal silver solutions, difference is that reaction temperature is 80 ℃.The exchange current density of reaction system is 330.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 85nm place.
Embodiment 78
As embodiment 67 preparation colloidal silver solutions, difference is to use glutathione rather than fructose, and reaction temperature is 60 ℃.Glutathione concentrations in the reaction system is 30g/L.The exchange current density of reaction system is 88.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 38nm place.
Comparative example 13
As embodiment 78 preparation colloidal silver solutions, difference is that reaction temperature is 80 ℃.The exchange current density of reaction system is 290.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 260nm place.
The result is as shown in table 12.Used symbol is as follows in the table:
The type of metallic compound
AgNO
3: silver nitrate
The type of reducing agent
MN: mannose
Et: ethanol
Ma: malic acid
GT: glutathione
The type of additive
NH
3: ammoniacal liquor
*D: polyvinylpyrrolidone (the K30 level: WAKO PURE CHEMICAL IND., LTD.)
pH
#1: the pH of silver nitrate ammonia spirit
#2: the pH of whole reaction system
Table 12
| Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size of silver powder (nm) | |||||||||
| Type | Concentration (g/L) | Type | Concentration (g/L) | Reaction temperature (℃) | Additive | pH (#1) | pH (#2) | Viscosity (mPas) | Reaction time (hr) | ||||
| Embodiment 75 | AgNO 3 | 26 | MN | 50 | 60 | NH 3 | *d | 11 | 8 | 1 | 1 | 15.0 | 8 |
| Embodiment 76 | AgNO 3 | 26 | Et | 5 | 30 | NH 3 | *d | 11 | 8 | 1 | 3 | 20.0 | 35 |
| Embodiment 77 | AgNO 3 | 26 | Ma | 13 | 25 | NH 3 | *d | 11 | 8 | 1.5 | 3 | 95.0 | 28 |
| Comparative example 12 | AgNO 3 | 26 | Ma | 13 | 80 | NH 3 | *d | 11 | 8 | 1.5 | 3 | 330.0 | 85 |
| Embodiment 78 | AgNO 3 | 26 | GT | 30 | 60 | NH 3 | *d | 12 | 8.5 | 3 | 3 | 88.0 | 38 |
| Comparative example 13 | AgNO 3 | 26 | GT | 30 | 110 | NH 3 | *d | 11 | 3 | 3 | 3 | 290.0 | 260 |
Found that by the embodiment shown in the table,, also can change the exchange current density of redox reaction, can change the particle size at platinum powder end thus by selective reduction agent from all cpds even other condition is identical.By the result of embodiment 77 and comparative example 12 and found that of embodiment 78 and comparative example 13, even under the situation of using the conventional reduction agent, if the exchange current density of redox reaction is controlled at 100 μ A/cm
2Or littler, then can by regularization condition for example reaction temperature further reduce the particle size of metal dust.
Comparative example 14
As embodiment 67 preparation colloidal silver solutions, difference is to use formalin rather than fructose, and reaction temperature is 60 ℃.Formalin concentration in the reaction system is 5g/L.The exchange current density of reaction system is 580.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 125nm place.
Comparative example 15
As embodiment 67 preparation colloidal silver solutions, difference is to use sodium borohydride rather than fructose, and reaction temperature is 60 ℃.Sodium borohydride concentration in the reaction system is 4g/L.The exchange current density of reaction system is 1800.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 600nm place.
Comparative example 16
As embodiment 67 preparation colloidal silver solutions, difference is to use riboflavin rather than fructose, and reaction temperature is 80 ℃, and the reaction time is 2 hours.Riboflavin concentration in the reaction system is 38g/L.The exchange current density of reaction system is 135.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 88nm place.
Comparative example 17
As embodiment 67 preparation colloidal silver solutions, difference is to use titanium trichloride rather than fructose, and reaction temperature is 5 ℃.The concentration of the titanium trichloride in the reaction system is 16g/L.The exchange current density of reaction system is 2500.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 8.Press embodiment 67 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 1200nm place.
The result is as shown in table 13.Used symbol is as follows in the table:
The type of metallic compound
AgNO
3: silver nitrate
The type of reducing agent
FA: formalin
NB: sodium borohydride
RF: riboflavin
TC: titanium trichloride
The type of additive
NH
3: ammoniacal liquor
*D: polyvinylpyrrolidone (the K30 level: WAKO PURE CHEMICAL IND., LTD.)
pH
#1: the pH of silver nitrate ammonia spirit
#2: the pH of whole reaction system
Table 13
| Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2 ) | The particle size of silver powder (nm) | |||||||||
| Type | Concentration (g/L) | Type | Concentration (g/L) | Reaction temperature (℃) | Additive | pH (#1) | pH (#2) | Viscosity (mPa s) | Reaction time (hr) | ||||
| Comparative example 14 | AgNO3 | 26 | FA | ?5 | 60 | NH3 | *d | 11 | 8 | 1 | 3 | 1800.0 | 580.0 |
| Comparative example 15 | AgNO3 | 26 | NB | ?4 | 60 | NH3 | *d | 11 | 8 | 1 | 3 | 135.0 | 125 |
| Comparative example 16 | AgNO3 | 26 | RF | ?38 | 80 | NH3 | *d | 11 | 8 | 1.5 | 2 | 2500.0 | 600 |
| Comparative example 17 | AgNO3 | 26 | TC | ?16 | 5 | NH3 | *d | 11 | 8 | 1.5 | 3 | 2500.0 | 88 |
Found that by the embodiment in the table, when the reducing activity of reducing agent is too high,, also the exchange current density of redox reaction can't be controlled at 100 μ A/cm even adjust other condition
2Or littler, therefore can't reduce the particle size of metal dust.
＜preparation bronze end 〉
Embodiment 79
Tetrachloro gold hydrohalogenic acid salt (III) tetrahydrate is dissolved in the deionized water, then will (the K25 level: WAKO PURE CHEMICAL IND. LTD.) be dissolved in this solution fully as the polyvinylpyrrolidone of big dispersal agent molecule.Then, will add in the muriatic solution of gold as the solution that the fructose of reducing agent prepares by dissolving in deionized water.Like this, make liquid-phase reaction system.Gold concentration in the reaction system is 41g/L, and fructose concentration is 50g/L, and the concentration of polyvinylpyrrolidone is 16g/L.
Then, placed 2 hours under 10 ℃ reaction temperature by making described reaction system, use magnetic stirring apparatus to stir under 1000rpm simultaneously, preparation shows the reddish violet colloidal gold solution that plasmon absorbs.The exchange current density that records reaction system by said method is 1.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 2.
The colloidal gold solution of centrifugal gained reaches 20 minutes repeatedly under 20000G, to remove than the light impurity in bronze end.Spend deionised water bronze end then.Use laser Doppler method, (the UPA 150EX:NIKKISO CO. of product serial number No.Microtrac LTD.) measures particle size distribution, and the result observes sharp peak at the 1.5nm place to adopt the particle size distribution analysis instrument.
Embodiment 80
As embodiment 79 preparation colloidal gold solutions, difference is that reaction temperature is 30 ℃.The exchange current density of reaction system is 2.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 2.Press embodiment 79 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 2nm place.
Embodiment 81
As embodiment 79 preparation colloidal gold solutions, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 15.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 2.Press embodiment 79 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 60nm place.
Embodiment 82
As embodiment 79 preparation colloidal gold solutions, difference is to use ascorbic acid rather than fructose, and reaction temperature is 5 ℃.The concentration of the ascorbic acid in the reaction system is 26g/L.The exchange current density of reaction system is 70.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 2.Press embodiment 79 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 25nm place.
Embodiment 83
As embodiment 82 preparation colloidal gold solutions, difference is that reaction temperature is 30 ℃.The exchange current density of reaction system is 80.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 2.Press embodiment 79 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes sharp peak at the 55nm place.
Comparative example 18
As embodiment 82 preparation colloidal gold solutions, difference is that reaction temperature is 60 ℃.The exchange current density of reaction system is 300.0 μ A/cm
2Under this reaction temperature, the viscosity of reaction system is 1mPas, and pH is 2.Press embodiment 79 and handle after the colloidal silver solution of gained, measure the distribution of particle size.The result observes broad peak at the 400nm place.
The result is as shown in table 14.Used symbol is as follows in the table:
The type of metallic compound
TCAu: tetrachloro gold hydracid (III) tetrahydrate
The type of reducing agent
FL: fructose
As: ascorbic acid
The type of additive
NH3: ammoniacal liquor
*E: polyvinylpyrrolidone (the K25 level: WAKO PURE CHEMICAL IND., LTD.)
Table 14
| Metallic compound | Reducing agent | Reaction system | Exchange current density (μ A/cm 2) | The particle size at bronze end (nm) | |||||||
| Type | Concentration (g/L) | Type | Concentration (g/L) | Reaction temperature (℃) | pH | Viscosity (mPas) | Additive | Reaction time (hr) | |||
| Embodiment 79 | TCAu | 41 | FL | ?50 | 10 | 2 | 1 | Do not have | 2 | ?1.0 | 1.5 |
| Embodiment 80 | TCAu | 41 | FL | ?50 | 30 | 2 | 1 | Do not have | 2 | ?2.0 | 2 |
| Embodiment 81 | TCAu | 41 | FL | ?50 | 60 | 2 | 1 | Do not have | 2 | ?15.0 | 60 |
| Embodiment 82 | TCAu | 41 | As | ?26 | 5 | 2 | 1 | Do not have | 2 | ?70.0 | 25 |
| Embodiment 83 | TCAu | 41 | As | ?26 | 30 | 2 | 1 | Do not have | 2 | ?80.0 | 55 |
| Comparative example 18 | TCAu | 41 | As | ?26 | 60 | 2 | 1 | Do not have | 2 | ?300.0 | 400 |
Found that by the embodiment shown in the table, can reduce the exchange current density of redox reaction by reducing reaction temperature, and can reduce the particle size at platinum powder end thus.
Industrial applicibility
Use the method for manufacturing metal dust of the present invention, can prepare the catalyst with following structure: noble metal for example the powder deposition of platinum in carrier particle surface. The catalyst that obtains is through for example filtering, wash, can being used for fuel cell and waste gas purification after drying and the activation process.
And, use the method for manufacturing metal dust of the present invention, can provide by powder being dispersed in decentralized medium and for example make the powder that is colloidal state in water or the organic solvent, the powder that is pulverulence by processings manufacturings such as powder being filtered, wash, be dry perhaps is provided, and it for example can be used as the pigment for the production of ink jet or electrocondution slurry. For example, can be by ink-jet printer, use gold for example or silver powder to form electric wiring as the ink jet of conducting pigment at printed substrate, perhaps can be by ink-jet printer, use gold for example or silver powder to carry out operplate printing as the ink jet of metallic pigments. In addition, can be by serigraphy, use gold for example or silver powder to form electric wiring as the electrocondution slurry of conducting pigment at printed substrate.
Claims (5)
1. method of making metal dust, it is by using reducing agent reduction metal ion to be precipitated in liquid-phase reaction system, so that precipitated metal is a metal powder granulates, wherein the exchange current density of the redox reaction between metal ion and reducing agent is 100 μ A/cm
2Or under the littler condition, reducing described metal ion, described exchange current density is determined by mixed potential theory.
2. the method for the manufacturing metal dust of claim 1, wherein said reducing agent is reduced sugar or sugar alcohol.
3. the method for the manufacturing metal dust of claim 1 wherein by the described metal ion of reduction under the condition that carrier granular is dispersed in the liquid-phase reaction system, is deposited on the surface of carrier granular metal powder granulates.
4. the method for the manufacturing metal dust of claim 3, wherein said carrier granular is carbon or inorganic compound particle.
5. the method for the manufacturing metal dust of claim 1, wherein metal ion is reduced in liquid-phase reaction system, so that metal powder granulates precipitates independently of one another.
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| CN102458727A (en) * | 2009-04-24 | 2012-05-16 | 独立行政法人科学技术振兴机构 | Fine solid solution alloy particles and method for producing same |
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