TW201138959A - A modified catalyst, its preparation method and uses thereof - Google Patents

Abstract

Provided herein is a modified catalyst. The modified catalyst includes a support, and a metal absorbed thereon. The absorbed metals include a precious metal and an alkaline earth metal. The precious metal includes platinum and ruthenium, which is about 3 wt% in the catalyst. The alkaline earth metal includes magnesium, and is about 0.25 - 2 wt% in the catalyst. According to one example of the present disclosure, the support is zirconium oxide. The method of making the modified catalyst and its use in producing hydrogen are also disclosed.

Description

201138959 VI. Description of the Invention: [Technical Field] The present invention relates to a modified catalyst, in particular, a catalyst modified by an alkaline earth metal to make the modified medium have better low temperature activity and low temperature A lower amount of carbon monoxide is produced in the ethanol process. [Prior Art] Hydrogen can be used in a hydrogen fuel cell to react with oxygen to generate electricity, and Lu hydrogen as a fuel can reduce greenhouse gas emissions, and hydrogen has high energy conversion efficiency, and the noise during operation is small. At present, the source of hydrogen is mainly to decompose and recombine fossil fuels, and to store the produced hydrogen in a gas cylinder or a gas tank, and then send it to each place through the transport system, so this method will generate a large amount of transportation. cost. If the organic matter with high energy density can be catalytically decomposed to generate hydrogen by means of chemical reaction, the cost of transporting hydrogen can be greatly reduced. Steam reforming of ethanol (SRE) is a method for producing hydrogen by a high temperature catalytic reaction of an aqueous ethanol solution. In the prior art, an alkali metal group metal has been used to modify a platinum-ruthenium catalyst for use in an Oxidative steam reforming of ethanol (OSRE) reaction. There is a need in the art for an improved catalyst that has better catalyst activity and can be used in ethanol vapor recombination reactions to produce hydrogen without producing high amounts of other undesirable by-products, such as carbon monoxide. SUMMARY OF THE INVENTION 201138959 Based on the above object, the inventors of the present invention provide a novel modified catalyst which has better catalytic activity and stability in low temperature ethanol vapor recombination reaction, and can reduce hydrogen production reaction in ethanol. The amount of co produced. According to a first aspect of the invention, a modified catalyst is provided. The modified catalyst comprises a support and a starting, bismuth and magnesium metal on the support, wherein platinum, bismuth and magnesium metal are respectively adsorbed on the support, wherein the weight of the magnesium metal accounts for about the total catalyst Between 0.25 and 2% by weight of the weight, the contents of platinum and rhodium are respectively about 1.5% by weight based on the total weight of the catalyst. According to an embodiment of the invention, the support is zirconia. According to a preferred embodiment of the invention, the weight of the magnesium metal is about 1% by weight based on the total weight of the modified catalyst. According to a second aspect of the present invention, there is provided a method of making the above modified catalyst. The method of the invention comprises the following steps. Platinum and rhodium metal in a metal solution containing platinum and rhodium are plated on the support by incipient wetness. Next, the support plated with platinum and base metal was calcined at 400 °C for 4 hours to produce a catalyst. The magnesium metal in the solution of the sulphuric acid is again plated on the platinum-ruthenium catalyst by the incipient wetness method to thereby produce a modified catalyst. According to one embodiment, the support is zirconia and the zirconia support is further calcined at 400 ° C for about 4 hours. According to another embodiment, the metal solution containing platinum and ruthenium is formed by dissolving vaporized platinum (PtCl 4 ) and ruthenium chloride (RuC 13 ) in water, and vaporizing platinum and ruthenium chloride in the metal solution. The concentration is about 1.5% (% by weight) each. The method further comprises subjecting the platinum-plated and base metal-plated support to a temperature of about 110 ° C for 24 hours prior to calcination. According to a third aspect of the present invention, there is provided a method of producing hydrogen gas at 201138959 using the above modified catalyst. The method comprises: reducing the modified catalyst of the present invention at a temperature of about 300 ° C for about 2 hours; and passing the aqueous ethanol solution through the reduced modified touch at a temperature of about 175-325 ° C The medium is used to catalyze the aqueous solution of ethanol to produce a hydrogen-containing gas. According to an embodiment of the invention, the reducing step comprises reducing using a mixed gas having a volume ratio of hydrogen to nitrogen of about 1:9. According to another embodiment of the present invention, the concentration of the aqueous ethanol solution is about 20% by volume. According to an embodiment, the temperature in the step of passing the aqueous ethanol solution through the reduced modified catalyst is about 250 ° C, at which temperature the hydrogen conversion rate of the process is about 100%. According to another example, the process produces a CO production rate of about 1% at about 275 °C. [Embodiment] In order to solve the shortcomings in the prior art that it is impossible to completely convert ethanol into hydrogen at a low temperature and to further reduce the amount of carbon monoxide generated, the inventors of the present invention improved this by adding magnesium metal to a known platinum-ruthenium catalyst. Platinum-ruthenium catalyst activity. It has been found that when the reformed catalyst is used to carry out the ethanol vapor recombination reaction (SRE), the amount of carbon monoxide (CO) by-product produced can be caused by the magnesium added to the catalyst at low temperatures. The amount of CO product decreases while increasing the activity of the catalyst. According to one aspect of the present invention, a magnesium-modified platinum-ruthenium catalyst is provided. The modified catalyst comprises a support and platinum, rhodium and magnesium metal plated on the support, wherein platinum, rhodium and magnesium metal are respectively adsorbed on the support, wherein the weight of the magnesium metal accounts for about the total catalyst The weight of 〇.25-2% (% by weight), platinum and rhodium are respectively about 1.5% by weight based on the total weight of the catalyst. According to a preferred embodiment of this aspect of the invention, the weight of the magnesium metal is about 1% by weight based on the total weight of the modified catalyst. Accordingly, another aspect of the present invention provides a method for preparing the above-described magnesium-modified platinum-ruthenium catalyst. The method comprises the following steps: 0) plating platinum and rhodium metal in a metal solution containing platinum and rhodium on a support by incipient wetness impregnation; (b) supporting the platinum-plated and rhodium-plated support at 4 〇〇 烺 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 The modified catalyst is produced. The support suitable for use in the process of the present invention is produced by a sol-gel method using a burned oxide of a Group IVB metal as a starting material. The sol-gel method is simply a method of hydrolyzing and condensing a metal oxide oxide from a solution to produce a colloid having a crosslinked structure. The mode of operation is as follows: First, an appropriate amount of the Group IVB metal oxide oxide, for example, n-butyl zirconia (IV), is dissolved in ethanol. Next, the above-mentioned ethanol solution containing the alkoxide of the Group IVB metal is dropped into the deionized water dropwise, so that the hydroxide of the Group IVB metal is precipitated, for example, by precipitation of barium hydroxide. Then, 'the precipitate of the hydroxide is collected by filtration, and then subjected to preliminary treatment such as washing with water, drying, etc.', and then the dried precipitate is subjected to calcination treatment to obtain the desired Group IVB metal (for example, oxidized hammer) support. . According to an example, a suitable calcination temperature is from 300 to 500 t and the time is from about 3-5 hours. Group IVB metal oxide supports suitable for use in the modified catalyst of the present invention prepared in the manner described above include, but are not limited to, titanium oxide, zirconium oxide or hafnium oxide. In one embodiment, the support is zirconia. 201138959 In the manufacturing method, a metal which can be used as a catalyst, including a noble metal (for example, platinum and rhodium) and an alkaline earth metal (for example, 'magnesium), is plated separately according to a wet impregnation (WI) method. The support made by the above method. The incipient wetness method is a commonly used technique and is mostly used to synthesize heterogeneous catalysts. Generally, the active metal precursor is first dissolved in water or an organic solvent. Next, the metal-containing solution is applied to the surface of the catalyst support, and the metal solution is sucked into the support by the capillary action of the pores of the catalyst support itself. After drying and calcining, the volatile components in the solution are removed, and the metal is deposited on the support to obtain the desired catalyst. In the step (a), a metal precursor comprising platinum tetrachloride (PtCl4) and ruthenium trichloride (RuCl3) is separately dissolved in deionized water to form a tetragastric turn (PtCU) and antimony trichloride. Metal solution of (R11CI3). Next, the metal solution was dropped onto the above-mentioned oxidized mis-branch by dropwise addition. In the step (b), the ruthenium oxide support to which the metal ions have been adsorbed is calcined at a temperature of 4 ° C for about 4 hours to prepare a platinum-ruthenium catalyst (PtRu/Zr〇2). . In one example, the platinum-ruthenium catalyst produced contains 1.5% by weight of platinum metal and 1.5% by weight of ruthenium metal, that is, the weight of platinum and rhodium metal is about 3% of the total weight of the media (3wt ° / . PtRu / Zr02). In the step (c), the alkaline earth metal (e.g., town) ore is again applied to the platinum-ruthenium catalyst as described above by the incipient wetness impregnation method to form the desired reforming catalyst. In short, a magnesium nitrate solution is first prepared. Then, this magnesium nitrate metal solution is dropped onto the above platinum-ruthenium catalyst in a dropwise manner. After drying and calcination (400 ° C, 4 hours), a modified platinum-ruthenium catalyst, PtRuMgx/Zr〇2 ', where X represents the weight of the adsorbed magnesium, 201138959, X Values can range from about 0.25% to about

percentage. According to an embodiment of the present invention, 2% by weight - the best example, magnesium metal (PtRuMg^/ZrOJ. The modified catalyst prepared according to the above method can be used in the reaction to catalyze the hydrogen production of ethanol, and the amount of simultaneous generation According to an embodiment,

At the same time, the conventional OSRE can effectively reduce the by-products (for example, c〇). The following methods will be used to make up the details of the catalyst, and the method of catalyzing the aqueous solution of ethanol and its products. analysis. EXAMPLES Example 1 Preparation of Magnesium-Modified Platinum-Nb Catalyst 1.1 Production of Platinum-Nb Catalyst (PtRu/Zr02) First, a catalyst support was prepared by a sol-gel method in the manner of operation. Briefly described as follows: Take an appropriate amount of n-butyl oxidized hammer (IV) solution and mix it with 99.5 /ί> of ethanol, then gradually drip into deionized water and stir for 3 hours. After that, white hydroxide is precipitated. After filtering and washing, it is dried at 110 〇c, and finally simmered under 4 Torr for 4 hours to obtain oxidized error (Zr〇2). It is to be understood that the amount of the n-butyl zirconia (IV) solution taken here depends on the amount of product to be formed, and the skilled artisan can determine the amount to be weighed according to the amount of the final product to be formed. .

The (by weight 4) shell metal (e.g., about 1.5% by weight of each of the ingots and bismuth) is deposited on the above-mentioned oxidized miscible material. In short, take appropriate amount of chlorinated surface (PtCU) and vaporized ruthenium (RuCl3), dissolve the two in deionized water, and gradually dilute the metal solution of 201138959 into the zirconia support. After the initial wet point, it is dried, dried at 110 °C for the whole night, and finally calcined at 4 °C for 4 hours to obtain a platinum-ruthenium catalyst (3 wt% PtRu/Zr〇2). . Similarly, the amount of gasified platinum and ruthenium chloride can be determined by one skilled in the art depending on the amount of final product desired to be formed. 1.2 Preparation of magnesium-modified platinum-ruthenium catalyst (PtRuMgx/Zr02) Prepare different weight percentages of the town metal solution, and also apply magnesium metal to the above platinum-ruthenium catalyst by incipient wetness method. Briefly, 0.25 %, 0.5 %, 1 %, and 2 % (wt%) aqueous solutions of nitrate are separately prepared, and then each of the separately prepared magnesium nitrate solutions is dropped into the above-mentioned platinum-ruthenium catalyst. Put on the 'after the initial wet point, dry and dry' into the oven for baking all night, you can get the lock-modified platinum-ruthenium catalyst (PtRuMgx/Zr〇2, where X represents the adsorption on the platinum_钌 catalyst Magnesium weight (% by weight), and X = 0·25, 〇.5, 1 or 2), and is named PtRuMg0 25/ZrO2, PtRuMg0 5/ZrO2, PtRuMg/Zr02 or PtRuMg/ZrO2, respectively. The prepared modified catalyst is stored in a sample vial until subsequent application. Example 2 The catalytic hydrogen production reaction of the low temperature ethanol was carried out by using the catalyst of Example 1. 2.1 Reduction treatment of the catalyst Before the catalytic hydrogen production by low temperature ethanol was carried out, the catalyst stored in the sample bottle, including the platinum-ruthenium catalyst, was first used. And modified catalyst (PtRuMgx/Zr02), subjected to crushing, crushing, sieving (mesh 60-80) treatment, and then at a temperature of 3 ° C with a volume ratio of hydrogen: nitrogen of about 1: 9 (3⁄4) : Nfl : 9) The mixed gas is reduced for about 2 hours to remove ions. After the source treatment, the 201138959 catalyst can be used in the low-temperature ethanol hydrogen production process. 2.2 Low temperature ethanol hydrogen production process

0.1 g of the above reduced treated catalyst was placed in a tubular reactor 110 covered with a heating belt 108 as shown in Fig. 1. Thereafter, the aqueous ethanol solution (20% (% by volume)) in the feed volume 102 was injected through the liquid pump 1〇4 and the gas (Ar) to inject the mixture at a rate of 14.7 ml/min. It was heated and gasified, and the flow rate of the carrier gas was set to 22 ml/min. Thereafter, the mixed gas is introduced into the tubular reactor 110 to react with the above-mentioned reduced modified catalyst. The total flow rate of the mixed gas is controlled to be about 36.7 ml/min. The tubular reactor 110 is heated at the extraction stage. The temperature of the tubular reactor 110 is first preset between about 175 and 325 °C. The ethanol solution vapor was continuously fed at a preset temperature for 2 hours in the tubular reactor 110 after reacting with the reduced reforming catalyst, and the reactants were passed to the analyzer 112 for product separation and analysis. Thereafter, the tubular reactor 110 is heated to the next reaction temperature to carry out a reaction. The product was separated by gas chromatography (GC). This gas chromatograph uses two chromatography columns, porapak Q and MS-5A, for product separation. The porapak Q column can be used to separate C02, C2H4, H20, CH3CH0 and C2H5OH, while the MS-5A column can be used to separate H2, 02, CH4 and CO. Thereafter, the product was quantitatively analyzed by a Thermal Conduction Detector (TCD) and the ethanol conversion rate (CEt0H), hydrogen yield (Yh2), and carbon dioxide product distribution (FC〇2) were calculated according to the following equation.

=riEt〇H—n nEtOH~out x|Q〇% nEtOH-in [S3 11 201138959

Y Η, one Η 2

Out

11 CH jCHO -out + — Π 2 C3H60-out

_nCQ2-out_ nH2-〇ut + nCH4-〇ut Seven nCO~ou! + nC〇2-out + nC3HbO-ow xlOO% The gas hour space velocity (GHSV) entering the gas chromatograph per hour is set to 22000I1-1, the water-alcohol ratio is 13, and the total time of the modified catalyst (PtRuMgx/Zr02) is 24 hours, and the reaction time at each temperature is the accumulation time. The results are provided in Tables 1-4 and 2-6 below, respectively. Tables 1 and 2 provide the reactant yield and analysis results, including YH2 yield (%), when PtRu/Zr02 is used for low-temperature hydrogen production. ), Fc〇2 yield (%), hydrogen (H2)/ethanol molar ratio, and ethanol conversion rate (%). Table 1 Catalyst reaction temperature (°C) Ethanol conversion rate (%) H2 yield (%) CO yield (%) C02 yield (%) CH4 yield (%) PtRu/Zr〇2 200 37.6 53 9.2 1.6 5.4 225 60.9 58.1 8.8 2.5 12.1 250 84.8 57.1 10.6 5.2 17.2 275 100 60.4 9.4 9.1 18.9 300 100 62 _ 】9 19 325 100 64.5 • 18.6 17

Tables 2 and 3 provide low-temperature nitrogen production by PtRuMg〇.25/Zr〇2 [s] 12 201138959, the reaction yield and analysis results, including yH2 yield (%), fC02 yield (% ), hydrogen (h2) / ethanol molar ratio and ethanol conversion rate (%). Catalyst reaction temperature (°C) Ethanol conversion rate (%) H2 yield (%) CO yield (%) co2 yield (%) CH4 yield (%) PtRuMg〇.25/Zr02 200 18 56.5 8.9 - 9.2 225 25.9 57.4 9.3 1.4 13.6 250 54.1 56.4 12.4 2.4 18.6 275 92 60.2 11.4 4.8 21 300 100 64 7.7 7.1 21 325 100 68.1 - 10.5 21.5

Tables 3 and 4 provide the reactant yield and analysis results for the low-temperature hydrogen production reaction with PtRuMg0.5/ZrO2, including YH2 yield (%), FC02 yield (%), hydrogen (H2)/ethanol. Mohr ratio and ethanol conversion rate (%). Catalyst reaction temperature CC) Ethanol conversion rate (%) H2 yield (%) CO yield (%) C〇2 yield (%) CH4 yield (%) PtRuMg〇, 5/Zr〇2 200 11.4 53.3 5.9 1.3 4.3 225 30 53.5 8.2 1.5 6.1 250 65.4 62.5 7.5 6.4 11.6 275 96.5 66 4.1 13 16.4 300 100 68 - 14.1 18 325 100 69.4 - 14.2 16.4 [S1 13 201138959 Tables 4 and 5 provide low temperatures with PtRuMg/Zr〇2 The reactant yield and analysis results in the hydrogen production reaction, including Yh2 yield (%), ruthenium ratio (%), hydrogen (H2) / ethanol molar ratio, and ethanol conversion rate (%). Table 4 Reaction temperature CC) A-age silk 4 & inflammation ___ catalyst ^ open to contend for (%) H2 yield (%) CO yield (%) C 〇 2 yield (%, CH4 yield 〇 / \ 175 11.2 Γ — 50.5 \/ϋ7 1.6 (%) 200 54.1 57.2 12.6 4.7 13 PtRuMgi/Zr〇2 225 83.2 58.2 13.5 4.7 16 250 100 62.8 11.8 10 15 275 100 66.8 Section 18.6 14.6 300 100 66 - 17.3 16.7 Table 5 And Fig. 6 provides the reactant yield and analysis results when the low-temperature hydrogen production reaction is carried out with ptRuMg2/Zr〇2, including YH2 yield (%), 匕〇2 yield (%), and atmosphere (H2)/ethanol. Mohr ratio and ethanol conversion rate (%). Table 5 Catalyst reaction temperature (°C) Ethanol conversion rate _ (%) H2 yield (%) CO yield (%) C〇2 yield (%) CH4 yield (%) PtRuMg2/Zr〇2 200 18.6 56.6 - 12 225 23.9 51.4 9.5 5 17.2 250 48.8 51.4 12 7.7 22.6 275 73.7 50.1 — 11.2 10 24 300 100 52.8 7.7 16 23.4 325 100 52 ----1 27 20.8

LSI 14 201138959 Comparing the above results, it can be found that the increase in the content of the catalyst with the modification of the magnesium after the modification of magnesium has increased its activity and improved the effect of C〇 water vapor transfer. However, adding an excessive amount of magnesium will reduce the efficiency, so find the best catalyst (see Table 4 and Figure 5) from the above results, and understand that the optimum content of magnesium added is 1 wt%; If the amount of magnesium adsorbed is excessive, the activity will start to decrease (see Tables 5 and 6). In summary, ptRuMg"Zr〇2 is the best modified catalyst for the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an ethanol catalyst device which can be used in the specific embodiment of the present invention; FIG. 2 is a conventional catalyst PtRU/Zr〇2 produced according to Example 1.1 of the present invention, The product of catalyzing the conversion of ethanol at different temperatures, and the whitening of the image is shown in Fig. 3 according to the embodiment of the present invention.

PtRuMgG.25/Zr〇2, which catalyzes the production of ethanol at different temperatures. FIG. 4 is a diagram made according to the embodiment of the present invention, PtRuMg0.5/Zr〇2' at different temperatures. The production of the lower catalytic ethanol is not changed. "The catalytic catalyst is shown in Fig. 5 as a pattern according to the embodiment of the present invention.

PtRuMg, /Zr02, which catalyzes the change of the product of the ethanol-modified catalyst at different temperatures. Fig. 6 shows the M' made according to the embodiment 1.2 of the present invention.

PtRuMfe/ZrO2' catalyzes the change in the product of ethanol = modified catalyst at different temperatures. [Main component symbol description] ES] 201138959

100 Ethanol Catalyst 102 Inlet Container 104 Liquid Pump 106 Mixing Tank 108 Heating Belt 110 Catalyst Bed 112 Analytical Instrument [s] 16

Claims (1)

201138959 VII. Patent application scope: L A modified catalyst, including · a support; and its medium = white 4 gold 24 ^ gold 4 ' points __ branch building ' \\ \ φ ^ one metal About the modified catalyst she ^ 1 & 1.5% (weight 〇 / 0), poetry a research only 'hoof, heart to summer 2% (% by weight). The genus accounts for about 0.25% of the total weight of the modified catalyst. L2! The modified catalyst described in the first paragraph of the patent scope, the support of the material is oxidized. 3. If the metal is about the catalyst, the 4. Method ' ^ (4) The material of the modified catalyst is 3=7 yam nails - and the nail 4 is coated with platinum and ruthenium metal support at 400 pm to produce a platinum-ruthenium Catalyst; The cerium impregnation method is applied to the platinum-ruthenium catalyst by plating the magnesium metal of the bismuth solution f, thereby producing the modified catalyst. 5. The method of claim 4, wherein the branch 17 • S] 201138959 is Zr02. 6. The method of claim 5, wherein the zirconia support is calcined at 400 ° C for about 4 hours. 7. The method of claim 4, wherein the metal solution comprising platinum and rhodium is formed by dissolving platinum chloride (PtCl4) and vaporized ruthenium (RuC13) in water, and vaporizing uranium and The concentration 气 of the vaporized ruthenium in the metal solution was about 1.5% by weight each. 8. The method of claim 4, wherein the magnesium metal comprises about 1% by weight of the total weight of the modified catalyst. 9. The method of claim 4, further comprising subjecting the platinum-plated and base metal-plated support to a temperature of about 110 ° C for 24 hours prior to calcination. 10. A method of catalytically producing argon comprising: reducing a modifying catalyst as described in claim 1 at a temperature of about 300 ° C for about 2 hours; at a temperature of about 175-325 ° C Next, an aqueous solution of ethanol is passed through the reformed modified catalyst to catalyze the aqueous solution of ethanol to produce a hydrogen-containing method 201138959, such as the method described in claim 10 of the Yinming patent (4), and the M step comprises hydrogen reduction for hydrogenation, and In the gas #4, the mixed gas of 1:9 is reduced. The volume ratio of L milk is about 12. The aqueous solution as described in the first aspect of the patent application contains about 20% by volume of ethanol. * The ethanol in the 13. The ethanol conversion rate described in the first paragraph of the patent application is about 1% in the case of 2 external helium. , the method of the method 14. The patent application range CO yield is 275. (: about 1%. The method of narration) where the method