CN102441375A - Homogeneous mesoporous rhodium oxide / alumina composite catalysis material, preparation method and application thereof - Google Patents
Homogeneous mesoporous rhodium oxide / alumina composite catalysis material, preparation method and application thereof Download PDFInfo
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Abstract
A preparation method of a homogeneous mesoporous rhodium oxide / alumina composite catalysis material of the invention comprises the following steps: (1) stirring a template and aluminum salt in absolute ethyl alcohol to obtain a homogeneous alumina sol; (2) dissolving rhodium salt in deionized water to prepare a solution, adding the solution into the alumina sol and carrying out ultrasonic disperse to obtain a rhodium oxide / alumina composite sol; (3) stirring the composite sol at room temperature and volatilizing solvent to obtain a rhodium oxide / alumina composite gel; (4) calcining the composite gel under 400-600 DEG C and removing the template to obtain the homogeneous mesoporous rhodium oxide / alumina composite catalysis material. The composite catalysis material can be applied to preparation of a methane catalysis combustion sensor and has beneficial effects of high specific surface area, loosening porous structure and capability of enhancing catalytic activity of a catalyst; the methane catalysis combustion sensor has characteristics of micromation, low power dissipation, short response time, high output signal, large signal to noise ratio, portability and convenience, etc.
Description
Technical field
The present invention relates to the synthetic and sensor technical field of inorganic material, relate to the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material and preparation method thereof and the application of said material on MEMS methane catalytic combustion sensor particularly.
Background technology
Mesoporous material has the orderly duct of queueing discipline, adjustable size and distribution extremely narrow aperture and surface and is easy to advantages such as chemical modification; Broken through the limited aperture of zeolite molecular sieve in the past, made the macromolecular absorption that much in zeolite molecular sieve, is difficult to accomplish, separate, carry out catalytic reaction and become possibility.In mesoporous catalytic field, really can play catalytic action or play synergistic those non-silicon mesoporous materials often with the catalyst of load.Therefore, the research of non-silicon-based mesoporous material is become an emerging in recent years subject, become a focus of new material research field.But, because non-silicon-based mesoporous material has variable chemical valence and relatively poor thermally-stabilised, it is synthetic be compared to silica-based more difficult.At present, the synthetic method of non-silicon-based mesoporous material mainly is to adopt hard template method.Owing to adopt mesopore silicon oxide as template, its preparation process is comparatively complicated, and cost is higher, has limited the practical application of non-silicon-based mesoporous material.
As far as the mesoporous catalysis material of noble metal, mainly be at present to adopt the method for load that it is loaded on the mesoporous carrier.This carrying method often has its limitation, and load capacity greatly very easily causes the duct obstruction, influences the performance of its catalytic action.Need the field of high-load noble metal catalyst at some, how to adopt that simple method is synthetic to have a high bullion content, the mesoporous precious metal catalyst material of high-ratio surface is a present catalytic field problem anxious to be solved.
In the application of sensor field, the detection to fuel gas in the industry mainly is to utilize catalytic combustion type sensor to carry out.The principle of catalytic combustion type sensor is: utilize a two-way electric bridge (generally being called " Wheatstone bridge ") detecting unit; Scribble the catalytic combustion material on the platinum wire electric bridge therein; No matter which kind of inflammable gas, as long as it can be ignited by electrode, the resistance of platinum wire electric bridge will change owing to variation of temperature; The concentration of this changes in resistance and fuel gas is proportional, the concentration that Circuits System and the microprocessor through instrument can calculate fuel gas.Wherein, the element that plays catalytic action is referred to as catalytic combustion element.
It is the Pt filament winding curl of 20～50 μ m that the catalytic combustion element of traditional noble metal wrapping wire generally uses diameter, and the coating alumina precursor solution sinters the alumina balls of diameter 1mm into, floods the noble metal catalyst sintering again and makes.But this element has two defectives:
First defective is: the mechanical strength of sensor catalysis element is not fine, and catalytic activity has decay after long-term the use.The Pt silk that adopts because of its wrapping wire is very thin; And often be in the cold cycling state (because gas concentration is different; The heat that catalytic combustion discharges can change, because of the loss of the different heats of gas flow rate also has difference), the vibration and the collision that often have of industrial environment in addition; Be easy to cause the fracture of wire of sensor catalysis element, cause component failure.In addition, the catalyst operating temperature is more than 500 degrees centigrade, and the active decay of sensor catalysis element is can hardly be avoided after long-time the use.
Second defective is: the power consumption of sensor catalysis element is high.In portable apparatus, for reducing the power consumption prolongs standby time, the Pt silk resistance that normally adopts is the bigger the better, and like this, the temperature effect of resistance will be obvious.But the Pt silk can not be done too carefully again, otherwise more is prone to the fusing phenomenon in using.
At present, to the use problem of portable apparatus, traditional fuel gas catalytic combustion sensor generally adopts high voltage (about 4.25 V), low current (> 50mA) catalytic combustion element, its power consumption is generally more than 200 mW.The 3600 mAh Li-Ion rechargeable batteries of generally selecting for use with portable apparatus calculate; The constant current work of 60 mA only can be kept 60 hours; Wherein also do not calculate the power consumption of mainboard chip, LCD; And portable apparatus can detect many gases often, therefore, also should consider the electricity consumption of other sensor.Therefore, the power consumption of reduction catalytic combustion sensor just seems very necessary.
The MEMS (Microelectro Mechanical Systems is called for short MEMS) and the manufacturing technology of microsensor are the shortcuts that addresses the above problem.MEMS (MEMS) compare with traditional sensor have that volume is little, in light weight, cost is low, low in energy consumption, reliability is high, be suitable for mass production, be easy to integrated and realize intelligentized characteristics.But, up to the present, also do not see report based on the catalytic combustion sensor of MEMS (MEMS).
Micro-heater based on the MEMS technology adopts the plane heater structure on the silicon chip, the situation that occurs opening circuit in the conventional catalyst combustion elements therefore can not occur.Again since the heating the Pt film thickness less than 0.1 μ m; Its resistance is far longer than the wrapping wire element (under general room temperature; The resistance of wrapping wire element is about 10 ohm, and the resistance of micro-heater can reach 200 ohm), the sensitivity that significant resistance temperature effect can improve sensor.At present, on the micro-heater that adopts based on the preparation of MEMS (MEMS) technology, prepare an important directions that has become the research of methane catalytic combustion sensor based on the low-power consumption methane catalytic combustion sensor (hereinafter to be referred as MEMS methane catalytic combustion sensor) of MEMS technology.
Said methane catalytic combustion sensor construction based on MEMS technology is: on based on the micro-heater thermal treatment zone of MEMS technology, apply the thin film substrate earlier, then coating catalyst layer again in substrate.But the thermal treatment zone area of this micro-heater is very little, is generally 0.01mm
2About, have only 1% size of conventional catalyst combustion elements, therefore very little by the catalytic amount of its load, consequently: the signal strength signal intensity that is produced by methane catalytic combustion in the measuring process is weak, signal to noise ratio is little, has a series of problems such as being difficult to practical application.
Summary of the invention
Technical problem to be solved by this invention is: one provides the preparation method of the mesoporous rhodium oxide of a kind of homogeneous phase/aluminium oxide compound catalyze material, can prepare high-specific surface area, noble content of metal, the mesoporous rhodium oxide of finely dispersed homogeneous phase/aluminium oxide compound catalyze material by described method; Two provide the application of described compound catalyze material on MEMS methane catalytic combustion sensor.
To the prior art problems of pointing out in the background technology, the present invention attempts aluminium oxide is introduced in the structure of mesoporous rhodium oxide under study for action, and the result finds: in very wide molar ratio range, rhodium oxide/aluminium oxide can both form the homogeneous phase meso-hole structure.The present invention continues above-mentioned meso-hole structure rhodium oxide/aluminium oxide catalyst layer is introduced MEMS methane catalytic combustion sensor under study for action, in the hope of increasing catalyst and detecting the area that gas effectively contacts.Introduce the MEMS methane catalytic combustion sensor of meso-hole structure catalyst layer, the load capacity of its catalyst improves greatly, and the effective contact area between methane and the catalyst significantly increases, thereby can obtain higher sensitivity.
For realizing above-mentioned purpose, the technical scheme that the present invention takes is:
The preparation method of the mesoporous rhodium oxide of a kind of homogeneous phase/aluminium oxide compound catalyze material is characterized in that its step comprises:
(1) template, aluminium salt are added in the absolute ethyl alcohol and stir, template: aluminium salt: the mol ratio of absolute ethyl alcohol is 1～2:10000:1000～2000, obtains the alumina sol of homogeneous after the dissolving;
(2) rhodium salt is dissolved in processes solution in the deionized water, add in the alumina sol that step (1) obtains again, the mol ratio R of rhodium and aluminium is 0＜R≤8 in the mixture of described solution and described alumina sol; After ultrasonic dispersion, obtain rhodium oxide/alumina composite sol;
(3) rhodium oxide/alumina composite sol that step (2) is obtained at room temperature stirs, and treats to obtain rhodium oxide/aluminium oxide plural gel after the solvent evaporates;
(4) rhodium oxide that step (3) is obtained/aluminium oxide plural gel is calcined under 400～600 ℃ of temperature, removes template, obtains target product---mesoporous homogeneous oxidizing rhodium/aluminium oxide compound catalyze material.
The described template of step (1) is one or more of F127 (Pluronic F127, PEO-PPO-PEO three block linear polymerics), P123 (nonionic surface active agent), CTAB (softex kw).
The described aluminium salt of step (1) is aluminum nitrate and hydrate or aluminium chloride and hydrate thereof.
The described rhodium salt of step (2) is radium chloride and hydrate or rhodium nitrate and hydrate or other soluble rhodium salt.
For realizing above-mentioned purpose, the technical scheme that the present invention takes is:
A kind of mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material according to above-mentioned method preparation; It is characterized in that; The mol ratio R of rhodium and aluminium is 0＜R≤8 in the said compound catalyze material; Rhodium oxide and aluminium oxide each other evenly disperse to form homogeneous, stable porous loose structure, and the material specific area is greater than 50 m
2/ g.
For realizing above-mentioned purpose, the technical scheme that the present invention takes is:
The mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material is in the application for preparing based on micro electro mechanical system (MEMS) technology in the methane catalytic combustion sensor.
The mesoporous rhodium oxide of said homogeneous phase/aluminium oxide compound catalyze material is characterized in that in the application for preparing based on micro electro mechanical system (MEMS) technology in the methane catalytic combustion sensor, is used for the detecting element of methane catalytic combustion sensor---the making of black element, and its step comprises:
(1) rhodium oxide/alumina composite sol is coated on the surface based on the micro-heater thermal treatment zone of MEMS technology preparation;
(2) said micro-heater is placed under 400～600 ℃ the high temperature handles,, promptly obtain black element at the mesoporous even rhodium oxide of the surface coverage of the micro-heater thermal treatment zone/aluminium oxide mesopore film.
For cooperating the use of catalysis element-Hei element that said method makes; Adopt meso-porous alumina colloidal sol to be coated on another surface based on the micro-heater thermal treatment zone of MEMS technology preparation; High-temperature process is removed the activating agent on micro-heater surface; Make the surface coverage meso-porous alumina film of the micro-heater thermal treatment zone, the white element of making element and above-mentioned black element (detecting element that is used for the methane catalytic combustion sensor) by way of compensation constitutes MEMS methane catalytic combustion sensor jointly.
Good effect of the present invention is:
(1) the mesoporous rhodium oxide of described homogeneous phase/aluminium oxide compound catalyze material has high-specific surface area and loose and porous structure; For the high capacity amount of noble metal active component provides feasibility; Strengthened catalytic activity, and considerable contact area has improved the sensitivity that catalysis element detects methane gas between methane gas and the catalyst.
(2) simple, the easy operating of the preparation method of the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material.
(3) rhodium oxide is uniformly dispersed on carrier; The structure and morphology homogeneous; Load capacity higher (Rh/Al mol ratio can up to 8:1) has good catalytic activity and heat endurance, meets the requirement of methane gas sensor for high sensitivity, fast gas response performance.
(4) through test; (be merely under the equal conditions traditional sensors 1/5) not only low in energy consumption when the MEMS methane catalytic combustion sensor based on the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material of the present invention is surveyed different concentration of methane gas under operating voltage, gas response time are short, and the output signal is high, signal to noise ratio is big.
(5) prepare the methane catalytic combustion sensor based on micro electro mechanical system (MEMS) technology and have microminiaturization, convenient portable characteristics.
Description of drawings
Fig. 1 is the preparation method's of the mesoporous rhodium oxide/aluminium oxide compound catalyze material of homogeneous phase of the present invention FB(flow block).
The FB(flow block) of Fig. 2 preparation methane catalytic combustion sensor that is the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material on based on micro electro mechanical system (MEMS) technology.
Fig. 3 is the TEM collection of illustrative plates of the mesoporous rhodium oxide/aluminium oxide of different rhodiums and aluminium (Rh/Al) mol ratio;
Label among the figure is respectively:
The mol ratio of a, rhodium and aluminium is 1:1;
The mol ratio of b, rhodium and aluminium is 2:1;
The mol ratio of c, rhodium and aluminium is 4:1;
The mol ratio of d, rhodium and aluminium is 8:1.
Fig. 4 is that the nitrogen of the mesoporous rhodium oxide/aluminium oxide of different rhodiums and aluminium (Rh/Al) mol ratio adsorbs back stagnate ring and graph of pore diameter distribution;
Label among the figure is respectively:
The mol ratio of a, rhodium and aluminium is 1:1;
The mol ratio of b, rhodium and aluminium is 2:1;
The mol ratio of c, rhodium and aluminium is 4:1;
The mol ratio of d, rhodium and aluminium is 8:1.
Fig. 5 is the wide-angle XRD figure spectrum of mesoporous rhodium oxide/aluminium oxide.
Fig. 6 is that rhodium and aluminium (Rh/Al) mol ratio are the XPS collection of illustrative plates of mesoporous rhodium oxide/aluminium oxide of 1:1.
Fig. 7 is the structure cutaway view of MEMS catalytic combustion sensing element;
Label among the figure is respectively: 1, catalyst film; 2, aluminum oxide film.
Fig. 8 is the structure vertical view of MEMS catalytic combustion sensing element.
Fig. 9 is the catalytic combustion type sensor circuit theory diagrams;
Label among the figure is respectively: 3, black element; 4, white element.
Figure 10 is under the 50%LEL methane concentration, black element operating voltage and output signal relation figure (temperature that identifies among the figure is the black platinum filament temperature of element under corresponding operating voltage).
Figure 11 is the signal graph that the MEMS catalytic combustion type sensor is exported down in different methane concentrations.
Figure 12 is the 50%LEL methane concentration, the graph of a relation of environment temperature and sensor output signal under the 25%RH humidity.
Figure 13 is the 50%LEL methane concentration, the graph of a relation of 25 degrees centigrade of following ambient humidities and sensor output signal.
Figure 14 poisons front and back signal output variation diagram for sensor;
Label among the figure is respectively:
A, feeding 100 ppm H
2Before S poisons;
B, feeding 100 ppm H
2After S poisons;
C, feeding 100 ppm H
2S and 50%LEL methane blended gas poison.
The specific embodiment
Provide the preparation method of the mesoporous rhodium oxide of homogeneous phase of the present invention/aluminium oxide compound catalyze material and, introduce below in conjunction with accompanying drawing based on the specific embodiment of the preparation method of the MEMS methane catalytic combustion sensor of the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material
5Individual embodiment.But be noted that enforcement of the present invention is not limited to following embodiment.
The preparation method of the mesoporous rhodium oxide of a kind of homogeneous phase/aluminium oxide compound catalyze material, its step comprises:
(1) with 1.0g P123,0.01mol aluminium salt (AlCl
3) be added in the 10ml absolute ethyl alcohol, under room temperature, stirred 60 minutes fast, obtain the meso-porous alumina colloidal sol of homogeneous after the dissolving;
(2) press rhodium salt (RhCl
3XH
2O) with aluminium oxide (AlCl
3) mol ratio is that the ratio of 1:1 is got an amount of rhodium salt and is dissolved in the deionized water, processes solution, adds in the aluminium colloidal sol that step (1) obtains again, and adopts the ultrasonic dispersion of Ultrasound Instrument 30 minutes, obtains rhodium oxide/alumina composite sol;
(3) rhodium oxide/alumina composite sol that step (2) is obtained is at room temperature dry, treats to obtain rhodium oxide/aluminium oxide plural gel after the solvent evaporates;
(4) rhodium oxide that step (3) is obtained/aluminium oxide plural gel is calcined under 550 ℃ of temperature, removes template, obtains the rhodium oxide/aluminium oxide compound catalyze material of mesoporous homogeneous phase, and its average pore size is 4nm, and specific area reaches 128.9 m
2/ g.
The preparation method of the mesoporous rhodium oxide of a kind of homogeneous phase/aluminium oxide compound catalyze material, its step comprises:
(1) (with embodiment 1);
(2) press rhodium salt (RhCl
3XH
2O) with aluminium oxide (AlCl
3) mol ratio is that the ratio of 2:1 is got an amount of rhodium salt and is dissolved in the deionized water, processes solution, adds in the aluminium colloidal sol that step (1) obtains again, and adopts the ultrasonic dispersion of Ultrasound Instrument 30 minutes, obtains rhodium oxide/alumina composite sol;
(3) (with embodiment 1);
(4) (with embodiment 1) obtains the rhodium oxide/aluminium oxide compound catalyze material of mesoporous homogeneous phase, and its average pore size is 4nm, and specific area reaches 112.3m
2/ g.
The preparation method of the mesoporous rhodium oxide of a kind of homogeneous phase/aluminium oxide compound catalyze material, its step comprises:
(1) (with embodiment 1);
(2) press rhodium salt (RhCl
3XH
2O) with aluminium oxide (AlCl
3) mol ratio is that the ratio of 4:1 is got an amount of rhodium salt and is dissolved in the deionized water, processes solution, adds in the aluminium colloidal sol that step (1) obtains again, and adopts the ultrasonic dispersion of Ultrasound Instrument 30 minutes, obtains rhodium oxide/alumina composite sol;
(3) (with embodiment 1);
(4) (with embodiment 1) obtains the rhodium oxide/aluminium oxide compound catalyze material of mesoporous homogeneous phase, and its average pore size is 4nm, and specific area reaches 101.4m
2/ g.
The preparation method of the mesoporous rhodium oxide of a kind of homogeneous phase/aluminium oxide compound catalyze material, its step comprises:
(1) (with embodiment 1);
(2) press rhodium salt (RhCl
3XH
2O) with aluminium oxide (AlCl
3) mol ratio is that the ratio of 8:1 is got an amount of rhodium salt and is dissolved in the deionized water, processes solution, adds in the aluminium colloidal sol that step (1) obtains again, and adopts the ultrasonic dispersion of Ultrasound Instrument 30 minutes, obtains rhodium oxide/alumina composite sol;
(3) (with embodiment 1);
(4) (with embodiment 1) obtains the rhodium oxide/aluminium oxide compound catalyze material of mesoporous homogeneous phase, and its average pore size is 4nm, and specific area reaches 51.5m
2/ g.
The shape characteristic of the rhodium oxide/aluminium oxide compound catalyze material of the mesoporous homogeneous phase that embodiment 1 to embodiment 4 is prepared is as shown in Figure 3, among the figure
A is the shape characteristic of the compound catalyze material under the 1:1 situation for the Rh/Al mol ratio of embodiment 1;
B is the shape characteristic of the compound catalyze material under the 2:1 situation for the Rh/Al mol ratio of embodiment 2;
C is the shape characteristic of the compound catalyze material under the 4:1 situation for the Rh/Al mol ratio of embodiment 3;
D is the shape characteristic of the compound catalyze material under the 8:1 situation for the Rh/Al mol ratio of embodiment 4.
The specific surface area data and the pore-size distribution of the rhodium oxide/aluminium oxide compound catalyze material of the mesoporous homogeneous phase that embodiment 1 to embodiment 4 is prepared are as shown in Figure 4, among the figure
A is the specific surface area data and the pore-size distribution of the compound catalyze material under the 1:1 situation for the Rh/Al mol ratio of embodiment 1;
B is the specific surface area data and the pore-size distribution of the compound catalyze material under the 2:1 situation for the Rh/Al mol ratio of embodiment 2;
C is the specific surface area data and the pore-size distribution of the compound catalyze material under the 4:1 situation for the Rh/Al mol ratio of embodiment 3;
D is the specific surface area data and the pore-size distribution of the compound catalyze material under the 8:1 situation for the Rh/Al mol ratio of embodiment 4.
Generally, noble metal and metal oxide containing precious metals are difficult to adopt soft template method directly to form meso-hole structure.But can know that from characterization result the present invention is template with the surfactant, only, can directly synthesize the loose porous meso-hole structure material of a series of different Rh/Al mol ratios with one-step method through adding a little aluminium oxide as additive.Shown in the TEM collection of illustrative plates of Fig. 3; In the synthetic material of different Rh/Al mol ratios; Do not have tangible metal or metal oxide nanoparticles and be attached to inside, duct or outside, the mesoporous composite material of the phase-splitting that forms between this point and other noble metal and oxide and aluminium oxide differs widely.
Nitrogen adsorption desorption test result shows that the rhodium oxide/aluminium oxide compound catalyze material of the mesoporous homogeneous phase of the present invention's preparation has meso-hole structure, the about 4nm of its pore size, and specific area also reduces along with the increase of rhodium content.Shown in Fig. 5 XRD figure spectrum, little angular region does not have diffraction maximum, and then the material duct is unordered shape; In the wide, 35 °, 58 ° strong diffraction maximums are corresponding to Rh
2O
3(114), (208) crystal face, Rh is described
2O
3Be certain crystallization state,, rein in the particle diameter that formula calculates rhodium oxide crystal grain and be about 1nm by thanking according to (114) diffraction maximum half-peak breadth.The XPS test result shows that there be (Fig. 6) in the rhodium element in the said compound catalyze material with the form of rhodium sesquioxide.
Embodiment 5
Referring to Fig. 2, the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material comprises the making of white element of methane catalytic combustion sensor and black element in the application for preparing based on micro electro mechanical system (MEMS) technology in the methane catalytic combustion sensor, and its step comprises:
(1) white element is made
1. the aluminium colloidal sol of embodiment 1 step (1) preparation is coated on the surface of micro-heater (methane catalytic combustion sensor) thermal treatment zone;
2. said micro-heater is handled under 600 ℃ of temperature, the template of removing in the gel (can repeat this process) covers mesoporous uniform aluminum oxide film fully until the surface of the micro-heater thermal treatment zone, obtains white element.
(2) black element is made
1. rhodium oxide/alumina composite sol is coated on the surface of micro-heater (methane catalytic combustion sensor) thermal treatment zone;
2. said micro-heater is handled under 550 ℃ of temperature; Template (can repeat this process) in removal rhodium oxide/alumina composite sol covers the mesoporous even rhodium oxide/aluminum oxide film with methyl hydride catalyzed activity fully until the surface of the micro-heater thermal treatment zone, and (the Rh/Al mol ratio is 1:1; See Fig. 7), obtain black element.
(3) the white element of step (1) being made is made methane catalytic combustion sensor with the black element that step (2) is made as the detecting element of methane catalytic combustion sensor as the compensating element, of methane catalytic combustion sensor.
Sensing element such as Fig. 7, shown in Figure 8 after described white element and the pairing of black element.It is to carry out sensor performance evaluation (Fig. 9) in the testing circuit board of design principle that sensing element is inserted with the Wheatstone bridge.
Test shows, MEMS LEL sensor be along with the increase of applied voltage, and self temperature raises, the rising in direct ratio with it of output signal, but power consumption also rises thereupon.Choose 1.3V as operating voltage, to guarantee that sensor shows high sensitivity (Figure 10) under lower power consumption, under 1.3V operating voltage, 50%LEL methane concentration, sensor output signal is 5mV, and power consumption is 25mW.Under equal conditions, be compared to traditional element, MEMS LEL sensor of the present invention has been exported the former 20% signal value with the former thermal treatment zone area of 1%, and power consumption is merely the former 1/5.Figure 11 has write down the signal value that sensor is exported under different methane concentrations under the 1.3V operating voltage, have good linear relationship between visible signal intensity and the methane concentration.Be to investigate the influence of environmental condition to sensor output signal, be constant at 25%RH at ambient humidity, methane concentration is under the 50%LEL condition, changes test environment temperature (20 ℃～40 ℃), signal of sensor does not have significant change (seeing Figure 12).On the other hand, be 25 ℃ at test environment, (it is comparatively stable that 25%RH～98%RH), sensor record the signal of output of 50%LEL concentration methane, is worth slightly with the humidity increase and is linear decrease corresponding to the different humidity environment.The same with the conventional catalyst combustion sensor, this influence can be eliminated (Figure 13) through related software.
Antitoxin voltinism can be tested (Figure 14) and shown, this sensor is feeding 100ppm H
2Before and after S 40 min poisoned, it had good antitoxin voltinism ability corresponding to the output signal of 50%LEL methane concentration no change almost.
The above is merely preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the present invention's design; Can also make some improvement and retouching, these improvement and retouching also should be regarded as in protection scope of the present invention.
Claims (8)
1. the preparation method of the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material is characterized in that its step comprises:
(1) template, aluminium salt are added in the absolute ethyl alcohol and stir, template: aluminium salt: the mol ratio of absolute ethyl alcohol is 1～2:10000:1000～2000, obtains the meso-porous alumina colloidal sol of homogeneous after the dissolving;
(2) rhodium salt is dissolved in processes solution in the deionized water, add in the alumina sol that step (1) obtains again, the mol ratio R of rhodium and aluminium is 0＜R≤8 in the mixture of described solution and described alumina sol; After ultrasonic dispersion, obtain rhodium oxide/alumina composite sol;
(3) rhodium oxide/alumina composite sol that step (2) is obtained at room temperature stirs, and treats to obtain rhodium oxide/aluminium oxide plural gel after the solvent evaporates;
(4) rhodium oxide that step (3) is obtained/aluminium oxide plural gel is calcined under 400～600 ℃ of temperature, removes template, obtains mesoporous homogeneous oxidizing rhodium/aluminium oxide compound catalyze material.
2. the preparation method of the mesoporous rhodium oxide of homogeneous phase according to claim 1/aluminium oxide compound catalyze material is characterized in that, the described template of step (1) is one or more of F127, P123, CTAB.
3. the preparation method of the mesoporous rhodium oxide of homogeneous phase according to claim 1/aluminium oxide compound catalyze material is characterized in that, the described aluminium salt of step (1) is aluminum nitrate and hydrate or aluminium chloride and hydrate thereof.
4. the preparation method of the mesoporous rhodium oxide of homogeneous phase according to claim 1/aluminium oxide compound catalyze material is characterized in that, the described rhodium salt of step (2) is radium chloride and hydrate or rhodium nitrate and hydrate or other soluble rhodium salt.
5. the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material according to the preparation of the described method of claim 1; It is characterized in that; The mol ratio R of rhodium and aluminium is 0＜R≤8 in the said compound catalyze material; Rhodium oxide and aluminium oxide each other evenly disperse to form homogeneous, stable porous loose structure, and the material specific area is greater than 50 m
2/ g.
6. the mesoporous rhodium oxide of homogeneous phase/aluminium oxide compound catalyze material is in the application for preparing based on micro electro mechanical system (MEMS) technology in the methane catalytic combustion sensor.
7. the mesoporous rhodium oxide of homogeneous phase according to claim 6/aluminium oxide compound catalyze material is in the application for preparing based on micro electro mechanical system (MEMS) technology in the methane catalytic combustion sensor; It is characterized in that, be used for the detecting element of methane catalytic combustion sensor---the making of black element.
8. the mesoporous rhodium oxide of homogeneous phase according to claim 7/aluminium oxide compound catalyze material is characterized in that in the application for preparing based on micro electro mechanical system (MEMS) technology in the methane catalytic combustion sensor making of said black element may further comprise the steps:
(1) rhodium oxide/alumina composite sol is coated on the surface of the micro-heater thermal treatment zone;
(2) said micro-heater is placed under 400～600 ℃ the high temperature handles,, promptly obtain black element at the mesoporous even rhodium oxide of the surface coverage of the micro-heater thermal treatment zone/aluminium oxide mesopore film.
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|---|---|---|---|---|
| CN105148564A (en) * | 2015-09-16 | 2015-12-16 | 浙江海洋学院 | Preparation method for super-hydrophilic and super-oleophobic oil-water separation net film |
| CN109304170A (en) * | 2017-11-16 | 2019-02-05 | 中国石油化工股份有限公司 | A kind of three-dimensional ordered mesoporous NM-Al catalyst, preparation method and application |
| CN109304172A (en) * | 2017-11-16 | 2019-02-05 | 中国石油化工股份有限公司 | A kind of high dispersing microporous/mesoporous Ag-Al catalyst, preparation method and applications |
| CN110865100A (en) * | 2019-12-18 | 2020-03-06 | 中国电子科技集团公司第四十九研究所 | Sheet-type structure integrated catalytic combustion type combustible gas sensor and preparation method thereof |
| CN113198467A (en) * | 2021-05-20 | 2021-08-03 | 贵州大学 | Preparation method and application of mesoporous aluminum oxide supported noble metal rhodium dehydrogenation catalyst |
| CN113603162A (en) * | 2021-08-04 | 2021-11-05 | 中国科学院广州地球化学研究所 | Near-spherical Rh2O3Preparation method of nano material |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105148564A (en) * | 2015-09-16 | 2015-12-16 | 浙江海洋学院 | Preparation method for super-hydrophilic and super-oleophobic oil-water separation net film |
| CN109304170A (en) * | 2017-11-16 | 2019-02-05 | 中国石油化工股份有限公司 | A kind of three-dimensional ordered mesoporous NM-Al catalyst, preparation method and application |
| CN109304172A (en) * | 2017-11-16 | 2019-02-05 | 中国石油化工股份有限公司 | A kind of high dispersing microporous/mesoporous Ag-Al catalyst, preparation method and applications |
| CN110865100A (en) * | 2019-12-18 | 2020-03-06 | 中国电子科技集团公司第四十九研究所 | Sheet-type structure integrated catalytic combustion type combustible gas sensor and preparation method thereof |
| CN113198467A (en) * | 2021-05-20 | 2021-08-03 | 贵州大学 | Preparation method and application of mesoporous aluminum oxide supported noble metal rhodium dehydrogenation catalyst |
| CN113603162A (en) * | 2021-08-04 | 2021-11-05 | 中国科学院广州地球化学研究所 | Near-spherical Rh2O3Preparation method of nano material |
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