A methanol reforming hydrogen production catalyst containing CuO and Cu2O thin film and a preparation method and application thereof

Abstract

The application provides a methanol reforming hydrogen production catalyst containing CuO and Cu2O films, which comprises a carrier, an active substance and an additive; the carrier is Al2O3 small spheres, a cordierite material honeycomb ceramic or the like, and there are interconnected nano through holes in the inside and surface of the carrier; the active substance is CuO and Cu2O films which are in-situ grown on the surface of the catalyst carrier and the inner surface of the nano through holes; and the additive is any one or a combination of multiple of CeO2, ZrO2 or the like. The application also provides a preparation method of the methanol reforming hydrogen production catalyst and application of the catalyst in methanol reforming hydrogen production. The active substance of the catalyst of the application is in-situ grown on the surface of the carrier and the inner surface of the pores, has good binding force, does not fall off, avoids performance degradation and dust pollution of the fuel cell end caused by powdering of the traditional catalyst, is not easy to powder, has high mechanical strength, and can adapt to complex working condition environments such as mobile / vibration of the application terminal and long-term work.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of energy chemical industry and new energy technology, and in particular to a methanol reforming hydrogen catalyst containing CuO and Cu2O thin film. BACKGROUND

[0002] With the development of science and technology and the progress of human civilization, today's society is undergoing a transition from the fossil energy era to the renewable energy era. Countries around the world have formulated their own new energy development strategies and carbon emission reduction targets. Compared with fossil energy such as oil and natural gas, hydrogen has the advantage of environmental protection, and its combustion product is water, which does not pollute the environment, and is an ideal zero-carbon fuel carrier. Combined with the increasingly mature fuel cell technology (such as proton exchange membrane fuel cells and solid oxide fuel cells), it can provide green, clean and stable power supply for various fields of society, and is an ideal green energy solution for future society. However, the storage and transportation technology of hydrogen is not mature, resulting in high cost of hydrogen use. At the same time, there is a great safety risk. Compared with hydrogen, methanol as a liquid fuel has a series of advantages such as high volumetric energy density, wide source, low price, low storage and transportation cost, safety and reliability, and is called the best new clean fuel at present. If methanol can be used to realize the on-site production of hydrogen at the application terminal, it is expected to solve the difficulty of hydrogen storage and transportation, and further promote the popularization and application of new energy technology.

[0003] Traditional methanol reforming hydrogen production technology is mostly aimed at large-scale hydrogen production. When the hydrogen production scale is simply reduced to small and medium scale (hydrogen production capacity is 100-3000 m 3 / h), there are often problems such as low catalytic activity, low liquid space velocity, low methanol conversion rate, high carbon monoxide content and easy pulverization of the catalyst, which are difficult to adapt to the actual working condition environment of fuel cell application terminals. Therefore, it is necessary to develop a methanol reforming hydrogen production technology suitable for small and medium scale to better meet the actual needs of fuel cells and other new energy technologies. Methanol reforming catalyst is the most core material to realize this technology. Traditional large-scale methanol reforming catalysts are not suitable for small and medium scale methanol reforming due to their low catalytic activity, large pore size and easy pulverization. At present, there is no mature catalyst for small and medium scale methanol reforming hydrogen production in China. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the above background technology, and to provide a methanol reforming hydrogen catalyst containing CuO and Cu2O thin film suitable for small and medium scale (hydrogen production capacity is 100-3000 m 3 / h) and its preparation method and application, which is composed of a catalyst carrier, an active substance and an additive.

[0005] To solve the above technical problems, the technical scheme provided by the present application is:

[0006] A methanol reforming hydrogen production catalyst containing CuO and Cu2O thin films, comprising a carrier, an active substance and an additive;

[0007] The carrier is an Al2O3 small ball, a cordierite material honeycomb ceramic, a foamed nickel, a foamed iron, a foamed copper or a foamed stainless steel, and there are interconnected nanochannels in the interior and surface of the carrier;

[0008] The active substance is a CuO and Cu2O thin film grown in situ on the surface of the catalyst carrier and the inner surface of the nanochannel; compared with the traditional Cu-based support, the existence form of the thin film is not easy to be pulverized, has good adhesion and can control the crystal face, and has better catalytic activity;

[0009] The additive is any one or a combination of multiple of CeO2, ZrO2, ZnO, Cr2O3, Ga2O3, Y2O3, MgO and CaO. The additive is impregnated and loaded at the interface between the catalyst active substance and the carrier, controls the growth direction of the active substance CuO and CuO2, and improves the bonding force between the active substance and the carrier.

[0010] Preferably, the mass ratio of the carrier, the active substance and the additive is (70-95):(4-20):(1-10).

[0011] Preferably, the diameter of the Al2O3 small ball is 0.5-30 mm; the Al2O3 small ball is composed of 10-20 nm Al2O3 particles, so that the interior and surface of the small ball form interconnected nanochannels with a pore size of less than 5 nm.

[0012] Based on the overall inventive concept, the present application also provides a preparation method of a methanol reforming hydrogen production catalyst containing CuO and Cu2O thin films, and the preparation steps are as follows:

[0013] (1) Dissolve the corresponding soluble metal salts of the active substance and the additive respectively in deionized water-organic alcohol / acid to form an organic alcohol / acid-metal salt solution;

[0014] (2) Dip the carrier in the organic alcohol / acid-metal salt solution obtained in step (1), filter, and then immerse the carrier loaded with the organic alcohol / acid-metal salt in a settling liquid, filter, and dry to obtain a carrier loaded with an active substance precursor;

[0015] (3) sinter the carrier obtained in step (2) in air, keep warm, and then cool to below the boiling point of the active substance precursor to obtain a catalyst carrier attached with a catalyst active substance thin film precursor;

[0016] (4) The catalyst carrier obtained in step (3) is placed in a reducing atmosphere for in-situ reduction to obtain a methanol reforming hydrogen catalyst containing CuO and Cu2O films.

[0017] The in-situ vapor deposition process refers to loading the catalyst active material precursor and the additive onto the surface and pores of the catalyst carrier and then sintering at high temperature in air. When the sintering temperature is higher than the boiling point of the precursor, supersaturated vapor of the precursor is formed inside the pores and on the outer surface. When the temperature is lowered to below the boiling point, the supersaturated vapor grows into a catalyst active material precursor film with specific texture structure under the synergistic regulation of the surface microstructure of the carrier and the catalyst additive. This process can not only form a nanoscale film with specific texture, but also significantly improve the bonding force of the film and the catalyst carrier and the uniformity of the distribution of the catalyst precursor on the inner and outer surfaces of the carrier.

[0018] The in-situ reduction process refers to placing the catalyst in hydrogen or methanol-water vapor mixture for in-situ reduction. In this process, the Cu2(OH)2SO4, Cu2(OH)2CO3 and Cu(CH3COO)2 films can be transformed into CuO and Cu2O films in-situ.

[0019] Preferably, the active material in step (1) corresponds to a soluble metal solution including any one or a combination of copper sulfate, copper nitrate, and copper chloride;

[0020] The additive corresponds to a soluble metal solution including any one or a combination of cerium nitrate, cerium ammonium nitrate, cerium acetate, cerium sulfate, cerium ammonium sulfate, zirconium nitrate, zirconium acetate, zirconium sulfate, zirconium chloride, zinc nitrate, zinc acetate, zinc sulfate, chromium nitrate, chromium sulfate, chromium chloride, gallium nitrate, gallium sulfate, gallium chloride, yttrium nitrate, yttrium acetate, yttrium sulfate, calcium nitrate, calcium acetate, magnesium nitrate, magnesium acetate, and magnesium sulfate;

[0021] The organic alcohol / acid includes any one or a combination of methanol, formic acid, ethanol, and propanol.

[0022] Preferably, the total metal cation concentration in the organic alcohol / acid-metal salt solution in step (1) is 0.1-5 mol / L, and the molar ratio of copper ions to additive metal ions in the organic alcohol / acid-metal salt solution is 20:1-2:1; the mass ratio of the organic alcohol / acid to deionized water in the deionized water-organic alcohol / acid is 0:1-2:1.

[0023] Preferably, the mass ratio of the carrier to the organic alcohol / acid-metal salt solution in step (2) is 1:10-2:1.

[0024] The active substance precursor in step (2) is a combination of one or more of Cu2(OH)2SO4, Cu2(OH)2CO3 and Cu(CH3COO)2;

[0025] The impregnation in step (2) is divided into vacuum impregnation and atmospheric pressure impregnation, the vacuum impregnation is performed at a pressure of <10 Pa and room temperature for 1-48 h, and the atmospheric pressure impregnation is performed at room temperature for 1-48 h.

[0026] The settling liquid in step (2) is an aqueous solution comprising one or more of a combination of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate and acetic acid, the concentration of the settling liquid is 0-5 mol / L, and the mass ratio of the carrier to the settling liquid is 1:10-2:1.

[0027] The baking in step (2) is performed at a temperature of 60-90 ℃ for 2.5-4.5 h.

[0028] Preferably, the sintering in step (3) is performed at a temperature increasing rate of 2-20 ℃ / min, a sintering temperature of 200-500 ℃ and a holding time of 5-300 min, and the cooling rate is 2-20 ℃ / min.

[0029] Preferably, the reducing atmosphere in step (4) is pure hydrogen or a mixture of methanol and water vapor, the molar ratio of methanol to water vapor in the mixture is 2:1-1:2, the in-situ reduction temperature is 150-300 ℃, and the reduction time is 5-600 min.

[0030] Based on the overall inventive concept, the application further provides an application of a methanol reforming hydrogen catalyst in methanol reforming hydrogen production, the catalyst can be used in the steam reforming of methanol at 150-300 ℃, the partial oxidation reforming of methanol or the cracking of methanol to produce hydrogen. The object of the catalyst catalysis is methanol, and the reaction equation is CH3OH(g)+H2O(g)→3H2+CO2.

[0031] Compared with the prior art, the application has the following beneficial effects:

[0032] 1. The catalyst of the present application, in terms of catalytic activity, the catalyst active substance CuO and Cu2O is in the form of nanometer-thick film grown in situ on the surface and inner surface of the carrier, through the regulation of the carrier and the adjuvant, the surface exposed by the active substance film is mostly high-activity surface, making the catalyst have higher catalytic activity per unit area compared with the traditional surface crystal phase randomly distributed granular catalyst; compared with the traditional loading, the form of the film is not easy to pulverize, has good adhesion and can be regulated in crystal face, and has better catalytic activity; in terms of specific surface area, the active substance is uniformly loaded on the surface and inner surface of the pores of the catalyst, and the specific surface area is > 200m 2 / g, the high specific surface area, high catalytic activity of the catalyst and large specific surface area make the catalyst of the present application be able to complete the reforming of methanol fuel in a smaller volume (< 100ml), which meets the actual demand of small-scale hydrogen production in the application terminal.

[0033] 2. The catalyst active substance of the present application is grown in situ on the surface of the carrier and the inner surface of the pores, has good binding force, and has the advantage of not falling off, such as the catalyst of the present application soaked in deionized water and methanol for one year, no powder falling phenomenon is observed, and the mechanical strength does not change, the above characteristics avoid the performance degradation and dust pollution problems of the fuel cell end caused by the pulverization of the traditional catalyst, are not easy to pulverize, have high mechanical strength, and can adapt to complex working conditions such as mobile / vibration and long-term work in the application terminal.

[0034] 3. The catalyst of the present application can inhibit the reaction process of generating carbon monoxide in the methanol reforming process through the regulation of the crystal face of the catalyst active substance film, promote the conversion process of carbon in methanol to carbon dioxide, and the content of carbon monoxide is low (< 1%), carbon monoxide is one of the main factors of Pt catalyst poisoning in the proton exchange membrane fuel cell, and the reduction of the content of carbon monoxide is expected to expand the application of the technology in the proton exchange membrane fuel cell end and simplify the subsequent processing process of the synthesis gas.

[0035] 4. The catalyst of the present application, the preparation method is simple, the cost is low, the thickness of the catalyst active substance coating is only several nanometers to several tens of nanometers, the amount of active substance is less than several tenths of the traditional catalyst, so the material cost of the catalyst is very low, not only can be used with the proton exchange membrane fuel cell and the solid oxide fuel cell for power generation based on methanol fuel, but also can be used in hydrogen supply terminals such as hydrogen stations.

[0036] 5. The catalyst of the present application has high liquid space velocity (>5h -1), the gas production rate of the unit volume reactor is fast, and the demand of the application terminal for gas supply can be met, which is mainly related to the high catalytic activity and high thermal conductivity of the catalyst. The high catalytic activity of the catalyst can catalyze a large amount of methanol in unit time, in addition, the thermal conductivity of the catalyst is > 30 W / (m·K), which is a good conductor of heat, and can meet the demand of heat transfer in the high load methanol reforming process; and the methanol conversion rate is high, the methanol conversion rate is > 99% when the liquid space velocity is > 5h -1 , and the efficient use of methanol fuel can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0038] Figure 1 It is a macroscopic morphology diagram of the methanol reforming catalyst of the present application;

[0039] Figure 2 It is a physical diagram of the methanol reformer;

[0040] Figure 3 It is a macroscopic morphology diagram of a domestic brand catalyst;

[0041] Figure 4 It is a comparison diagram of the catalyst disclosed in the present application and a domestic brand after reforming;

[0042] Figure 5 It is an HR-TEM diagram of the nanoscale coating of the methanol reforming catalyst of the present application;

[0043] Figure 6 It is a schematic diagram of the growth process of the nanometer-thick CuO / CuO2 film of the catalyst of the present application;

[0044] Figure 7 It is a schematic diagram of the reactor in Example 2;

[0045] Figure 8 It is a micro-morphology scanning electron microscope diagram (left) and a composition distribution diagram (right) of the methanol reforming catalyst of the present application in Example 2;

[0046] Figure 9 It is a physical diagram of the honeycomb ceramic carrier of the methanol reforming catalyst of the present application in Example 3;

[0047] Figure 10 It is a schematic diagram of the system of methanol catalytic reforming and SOFC coupling power generation;

[0048] Figure 11 The output power density evolution curve with time for the SOFC stack using the methanol reforming fuel gas to generate electricity;

[0049] Figure 12 The physical picture of the flexible nickel foam carrier catalyst for the invention in embodiment 4;

[0050] Figure 13 The cross-sectional schematic diagram of the flexible round sheet stacked catalyst for the invention in embodiment 4. DETAILED DESCRIPTION

[0051] In order to facilitate the understanding of the present application, the present application will be described in more detail and in a more complete, specific manner below in conjunction with the drawings of the specification and the preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0052] Unless otherwise defined, all the professional terms used herein have the same meaning as understood by those skilled in the art. The professional terms used herein are only for the purpose of describing the specific embodiments and are not intended to limit the scope of protection of the present application.

[0053] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0054] Embodiment 1:

[0055] This embodiment aims to illustrate the advantages of the catalyst active material film function of the present application and the feasibility of the corresponding catalyst for small and medium scale methanol steam reforming.

[0056] The catalyst of this embodiment is named Al-Cu-Ce, and the catalyst carrier used is a small ball with a diameter of about 3 mm composed of Al2O3 nanoparticles arranged according to the close packing rule; the catalyst active material precursor is Cu2(OH)2SO4, and the catalyst additive is CeO2, with a Cu to Ce molar ratio of 1:20; the reforming is methanol steam reforming, in which the molar ratio of methanol to steam is 2:1.

[0057] The preparation method of the reforming catalyst of this embodiment includes the following steps:

[0058] (1) Dissolve the copper sulfate corresponding to the catalyst active material and the cerium nitrate metal salt solution corresponding to the catalyst additive CeO2 in deionized water-ethanol, with a mass ratio of ethanol to deionized water of 2:1, a total concentration of Cu / Ce metal cations of 0.1 mol, and a molar ratio of additive Ce ions to active material Cu ions of 1:20; form an ethanol-Cu / Ce metal salt solution;

[0059] (2) Put the Al2O3 catalyst carrier into the ethanol-metal salt solution obtained in the above step to form a mixed solution, wherein the mass ratio of the Al2O3 catalyst carrier to the solution is 2:1;

[0060] Vacuum-impregnate the mixed solution in a vacuum environment for 48 h to ensure that the nanopores of the catalyst carrier are fully impregnated with the solution; the vacuum is <10 Pa in pressure and room temperature in temperature;

[0061] Take the vacuum-impregnated mixed solution out of the vacuum environment, and then immerse it in an atmospheric environment for 1 h at room temperature;

[0062] Filter the mixed solution after the atmospheric immersion to remove the solution that has not been impregnated into the carrier, and then immerse the carrier loaded with the ethanol-metal salt solution in a settling solution of sodium hydroxide to form a carrier loaded with the active substance precursor Cu2(OH)2SO4; the concentration of the settling solution of sodium hydroxide is 5 mol / L, and the mass ratio of the carrier loaded with the ethanol-metal salt solution to the settling solution is 1:10;

[0063] Filter the immersed mixed solution, and then bake the Al2O3 carrier loaded with the active substance precursor at 60°C for 2.5 h to obtain a catalyst carrier loaded with an active substance thin film precursor;

[0064] (3) First, sinter the baked Al2O3 balls in an air atmosphere at 500°C, and the holding time at the highest temperature is 5 h;

[0065] (4) Then, reduce the Al2O3 balls in a hydrogen atmosphere at 300°C for 5 min to obtain the catalyst of the present application; the temperature rising and falling rate during the sintering and reduction of the catalyst is 2°C / min.

[0066] The macroscopic morphology of the catalyst produced in the present embodiment is shown in Figure 1 The diameter of the small balls is about 3 mm. In order to verify the advantages of the catalyst produced in the present embodiment in the reforming of methanol vapor, the catalyst produced in the present embodiment is filled into a reforming tube as shown in Figure 2 , and then the reforming tube is placed in an oil bath for temperature rising reforming. The inner diameter of the reforming tube is 20 mm, and the length of the catalyst filled in the reforming tube is 300 mm. The molar ratio of methanol to water vapor used in the present embodiment is 2:1, and the reforming temperature is 300°C.

[0067] In order to verify the advantages of the catalyst produced in the present embodiment in the reforming of methanol vapor, a catalyst produced by a domestic brand (the morphology is shown in Figure 3The catalyst produced in this example was tested under the same reforming conditions as the catalysts shown in Table 1, and the composition of the reforming gas was detected by a chromatograph after the reforming tail gas was dried. The test results are shown in Table 1. The CuO / Cu2O film formed in situ in the catalyst improved the efficiency of methanol reforming, and the liquid space velocity of the catalyst produced in this example reached 5 h -1 , and the methanol conversion rate was as high as 99.88%, and the CO content in the reforming tail gas was as low as 0.3%. By collecting the catalyst after reforming, it was found that the commercial catalyst was severely pulverized, while the catalyst produced in this example was not easy to pulverize and had high mechanical strength, as shown in Figure 4 .

[0068] The active substance precursor Cu(OH)2SO4 and the additive CeO2 in the catalyst produced in this example were loaded on the surface and in the nanopores of the Al2O3 carrier by in-situ vapor deposition and sintered in air at 500°C. The over-saturation vapor of the precursor was formed inside the pores and on the outer surface. When the temperature was reduced below the boiling point, the over-saturation vapor grew into a catalyst active substance precursor CuO / Cu2O film with a specific texture structure under the synergistic regulation of the surface microstructure of the carrier and the catalyst additive. The process of gradually forming the characteristic nanocoating of the catalyst in the three steps of impregnation, evaporation, and reduction can be observed under a high-resolution electron microscope (as shown in Figure 5 ). In order to better illustrate the growth process of the nanofilm, we made a schematic diagram as shown in Figure 6 . The nanoscale CuO / Cu2O coating with a specific structure (as shown in Figure 5 ) has good binding force with the catalyst carrier Al2O3, which enhances the uniformity of the distribution of the catalyst precursor on the inner and outer surfaces of the Al2O3 beads. Compared with the traditional surface crystal phase randomly distributed granular catalyst, the catalyst has higher catalytic activity per unit area. Through the regulation of the carrier and the additive, the surface exposed by the active substance film is mostly high-activity surface, so that the catalyst has higher catalytic activity per unit area compared with the traditional surface crystal phase randomly distributed granular catalyst. The specific surface area of the sample is 215 m 2 / g, and the thermal conductivity is 42 W / (m·K).

[0069] As can be seen from the test results in Table 1, the catalyst produced in this example can realize high-quality reforming of methanol in a smaller volume (inner diameter 20 mm, length 300 mm), meeting the requirements of small and medium-sized carbon-based fuel reforming for catalysts.

[0070] Table 1 Chromatographic test results of methanol reforming gas components

[0071]

[0072] Example 2:

[0073] This embodiment is intended to illustrate the feasibility of the catalyst of the present application for partial oxidation reforming of methanol fuel.

[0074] The catalyst of this embodiment is named Al-Cu-Zr, the catalyst carrier used is a small ball with a diameter of about 2 mm composed of Al2O3 nanoparticles arranged according to the close packing rule; the catalyst active substance precursor is Cu2(OH)2CO3, the catalyst additive is ZrO2, and the molar ratio of Cu to Zr is 1:2; the reforming is partial oxidation reforming of methanol fuel, and the water / alcohol ratio reaches 1.5.

[0075] The preparation method of the reforming catalyst of this embodiment comprises the following steps:

[0076] (1) Dissolve the copper nitrate corresponding to the catalyst active substance and the zirconium nitrate metal salt solution corresponding to the catalyst additive ZrO2 in deionized water-ethanol, the mass ratio of ethanol to deionized water is 1:10, the total concentration of Cu / Zr metal cations in the formed organic acid / alcohol-metal salt solution is 5 mol, the molar ratio of the additive Zr ion to the active substance Cu ion is 1:2, and an ethanol-Cu / Zr metal salt solution is formed;

[0077] (2) Put the Al2O3 catalyst carrier into the ethanol-metal salt solution obtained in the above step to form a mixed solution, wherein the mass ratio of the Al2O3 catalyst carrier to the solution is 1:10;

[0078] Vacuum impregnate the mixed solution in a vacuum environment for 1 h to ensure that the nanopores of the catalyst carrier can be fully impregnated with the solution; the vacuum is a pressure <10 Pa, and the temperature is room temperature;

[0079] Take out the mixed solution after vacuum impregnation from the vacuum environment, and then immerse it in a normal pressure environment for 48 h, and the temperature is room temperature;

[0080] Filter out the solution that has not been impregnated into the carrier after normal pressure impregnation, and then immerse the carrier loaded with the ethanol-metal salt solution in a sodium carbonate settling solution to form a carrier containing the active substance Cu2(OH)2CO3 precursor, the concentration of the sodium carbonate solution is 1 mol / L, and the mass ratio of the carrier loaded with the ethanol-metal salt solution to the settling solution is 2:1;

[0081] Filter the immersed mixed solution, and place the Al2O3 carrier loaded with the catalyst active substance in an oven at 90°C for 3 h to obtain a catalyst carrier loaded with an active substance thin film precursor;

[0082] (3) First, sinter the Al2O3 ball after baking at 200°C in an air atmosphere, and the holding time at the highest temperature is 5 min;

[0083] (4) Subsequently, the Al203ball is put into a hydrogen atmosphere at 200°C for 10h to obtain the catalyst of the present application; the temperature rising and falling rate during catalyst sintering and reduction is 20°C / min.

[0084] To verify the effect of the catalyst produced in this embodiment on the partial oxidation reforming of methanol fuel, the catalyst is loaded into a reforming tube according to the structure shown in Figure 7 . Then the reforming tube is placed in an oil bath for the partial oxidation reforming of methanol. The inner diameter of the reforming tube is 20mm, and the length of the catalyst loaded is 300mm. The methanol and water are vaporized before reforming and then introduced into the reforming tube together with oxygen. The partial oxidation reforming is carried out at a temperature of 200°C and a liquid space velocity of 10h -1 . The micro-morphology and the composition scanning distribution of the catalyst produced in this embodiment after reforming are shown in Figure 8 . The tail gas after reforming is dried and then introduced into a chromatograph to detect the composition of the reforming gas.

[0085] The detection structure is shown in Table 2. As can be seen from the test results in Table 2, the catalyst of this embodiment can realize high-quality partial oxidation reforming of methanol in a small volume (inner diameter of 20mm, length of 300mm), meeting the requirements of small and medium-sized methanol fuel reforming on catalysts.

[0086] Table 2 Chromatographic test results of methanol reforming gas components

[0087]

[0088] Example 3:

[0089] This embodiment aims to illustrate that the disclosed catalyst can be directly used for external reforming of solid oxide fuel cells (SOFC).

[0090] The catalyst of this embodiment uses a cordierite honeycomb ceramic with a pore size of 1mm (shown in Figure 9 ) as the catalyst carrier. The catalyst active substance precursor is Cu(CH3COO)2, and the catalyst additive is ZnO, with a molar ratio of Cu to ZnO of 1:10. The reforming fuel is methanol.

[0091] The preparation method of the reforming catalyst of this embodiment includes the following steps:

[0092] (1) Dissolve the copper chloride corresponding to the catalyst active substance and the zinc sulfate metal salt solution corresponding to the catalyst additive ZnO in deionized water-ethanol, with a mass ratio of ethanol to deionized water of 1:1, to form an organic acid / alcohol-metal salt solution with a total concentration of Cu / Zn metal cations of 3mol, and a molar ratio of additive Zn ions to active substance Cu ions of 1:10, to form an ethanol-Cu / Zn mixed solution;

[0093] (2) Put the Al2O3 catalyst carrier into the ethanol-metal salt solution obtained in the above step to form a mixture, wherein the mass ratio of the Al2O3 catalyst carrier to the solution is 1:1, and the mixture is vacuum impregnated for 24 hours in a vacuum environment to ensure that the nanopores of the catalyst carrier are fully impregnated with the solution; the vacuum is <10 Pa in pressure and room temperature in temperature;

[0094] Take the vacuum-impregnated mixture out of the vacuum environment, and then immerse it in an atmospheric environment for 24 hours at room temperature;

[0095] Filter the solution in the mixture that has not been impregnated into the carrier after the atmospheric immersion, and then immerse the carrier loaded with the ethanol-metal salt solution in an acetic acid deposition solution to obtain a carrier containing the active substance precursor Cu(CH3COO)2, wherein the concentration of the acetic acid solution is 0.1 mol / L, and the mass ratio of the carrier loaded with the ethanol-metal salt solution to the deposition solution is 1:1;

[0096] Filter the immersed mixture, and bake the Al2O3 carrier loaded with the active substance precursor at 80°C for 3 hours to obtain a catalyst carrier loaded with an active substance thin film precursor;

[0097] (3) First, sinter the baked Al2O3 ball at 300°C in an air atmosphere, and the holding time at the highest temperature is 3 hours;

[0098] (4) Then, place it in a methanol-water vapor mixed gas to perform in-situ reduction at 280°C for 5 hours to obtain the catalyst of the present application; the temperature rising and falling rates during the sintering and reduction of the catalyst are 10°C / min.

[0099] To verify the effect of the catalyst produced in this embodiment on the external reforming of p-methanol in the SOFC stack, a system for coupling methanol catalytic reforming and SOFC power generation (a schematic diagram is shown in Figure 10 The methanol fuel is catalytically reformed in the external reforming tube, and then the reformed fuel gas is introduced into the anode of the stack, with a flow rate of 0.3 SLM, and air is introduced into the cathode, with a flow rate of 0.5 SLM. The output power density of the SOFC stack at 0.7 V constant voltage versus time is shown in Figure 11 During this test time, the output power density of the stack is relatively stable, and no obvious performance degradation is observed, indicating that the catalyst disclosed in the present application can well realize the combined power generation of methanol fuel gas and SOFC.

[0100] Example 4:

[0101] This embodiment aims to illustrate the advantages of the flexible carrier catalyst and the feasibility of using the corresponding catalyst for hydrogen production by methanol cracking.

[0102] The catalyst of the embodiment, the catalyst carrier used is a foamed nickel with a thickness of 20-50 mm and a diameter of 20 mm (a physical diagram is shown in Figure 12 The catalyst active substance precursor is a mixture of Cu2(OH)2SO4 and Cu2(OH)2CO3, and the catalyst additive is Cr2O3, with a molar ratio of Cu to Cr of 1:5. The reforming fuel is a methanol fuel.

[0103] The preparation method of the flexible reforming catalyst of the embodiment includes the following steps:

[0104] (1) Dissolve the copper sulfate corresponding to the catalyst active substance, the copper carbonate, and the chromium metal salt solution corresponding to the catalyst additive Cr2O3 in deionized water-ethanol, with a mass ratio of ethanol to deionized water of 1:3, to form an organic acid / alcohol-metal salt solution with a total concentration of Cu / Cr metal cations of 1.5 mol, and a molar ratio of the additive Cr ions to the active substance Cu ions of 1:5, to form an ethanol-CuCr mixed solution;

[0105] (2) Place the foamed nickel carrier in the ethanol-metal salt solution obtained in the above step to form a mixed solution, with a mass ratio of the foamed nickel carrier to the solution of 3:2, and vacuum-impregnate the mixed solution in a vacuum environment for 20 h to ensure that the nano-sized pores in the foamed nickel catalyst carrier are impregnated with the solution; the vacuum is <10 Pa in pressure and room temperature in temperature;

[0106] Take the vacuum-impregnated mixed solution out of the vacuum environment, and then immerse it in a normal pressure environment for 10 h at room temperature;

[0107] Filter the solution in the mixed solution that has not been impregnated into the carrier after normal pressure immersion, and then immerse the foamed nickel carrier loaded with the ethanol-metal salt solution in an acetic acid settling solution to form a carrier containing the active substance precursors Cu2(OH)2SO4 and Cu2(OH)2CO3, with an acetic acid solution concentration of 2.5 mol / L, and a mass ratio of the foamed nickel carrier loaded with the ethanol-metal salt solution to the settling solution of 1:5;

[0108] Filter the immersed mixed solution, and bake the foamed nickel carrier loaded with the active substance precursors at 75°C for 4.5 h to obtain a catalyst carrier loaded with an active substance thin film precursor;

[0109] (3) Roll the baked foamed nickel carrier in a rolling machine to make the active substance and the additive combine and become dense; then sinter the rolled foamed nickel carrier first in an air atmosphere at 380°C, with a holding time of 1.5 h at the highest temperature; then sinter it in a hydrogen atmosphere at 900°C for 1 h, and finally reduce it to room temperature to obtain a flexible foamed nickel catalyst carrier, with a temperature rising and falling rate of 5°C / min;

[0110] (4) The flexible catalyst is then placed in a methanol-water vapor mixture gas for in-situ reduction at 230°C for 3.5h to obtain the catalyst of the present application; the temperature rising and falling rate during catalyst sintering and reduction is 6°C / min.

[0111] To verify the advantages of the flexible catalyst produced in the present embodiment in methanol reforming, the flexible catalyst is stacked and loaded in a stainless steel reforming tube with an inner diameter of 20mm as shown in the schematic Figure 13 To verify the advantages of the flexible catalyst produced in the present embodiment in methanol reforming, the flexible catalyst is stacked and loaded in a stainless steel reforming tube with an inner diameter of 20mm as shown in the schematic The molar ratio of methanol and water vapor used in the present embodiment is 1:5, and the reforming temperature is 230°C; to verify the advantages of the flexible catalyst produced in the present embodiment and the feasibility of methanol cracking for hydrogen production, a catalyst produced by a certain brand abroad is tested under the same conditions, the reforming tail gas is dried by water removal, and the composition of the reforming gas is detected by a chromatograph, which is compared with the flexible catalyst of the present embodiment, and the test results are shown in the table. The flexible catalyst of the present embodiment can adapt to the shape of different reforming devices, and the combination of active substances and adjuvants is stronger, which exposes more active crystal surfaces and makes the catalytic effect more significant; at the same time, the flexible nickel foam catalyst carrier has good thermal conductivity, which can meet the heat transfer demand in methanol reforming, and makes the catalytic reduction more sufficient.

[0112] Table 3 Chromatographic test results of methanol reforming gas composition

[0113]

Claims

1. A catalyst for hydrogen production by methanol reforming comprising a thin film of CuO and Cu20, characterized in that, comprise a carrier, an active substance and an auxiliary agent; the carrier is Al2O3 beads or foamed nickel, and there are interconnected nanochannels in the interior and surface of the carrier; the active substance is a CuO and Cu2O film grown in situ on the surface of the carrier and the inner surface of the nanochannels; the auxiliary agent is a combination of any one or more of CeO2, ZrO2, ZnO and Cr2O3; the methanol reforming hydrogen production catalyst is prepared by the following steps: (1) dissolving the active substance and the auxiliary agent in deionized water-organic alcohol / acid respectively to form an organic alcohol / acid-metal salt solution; the organic alcohol / acid includes any one or a combination of more than one of methanol, formic acid, ethanol and propanol; (2) immersing the carrier in the organic alcohol / acid-metal salt solution obtained in step (1) and filtering to form a carrier loaded with organic alcohol / acid-metal, and then immersing the carrier in a settling solution, filtering and drying to obtain a carrier loaded with an active substance precursor; the active substance precursor is a combination of one or more of Cu2(OH)2SO4, Cu2(OH)2CO3 and Cu(CH3COO)2; the immersing is vacuum immersing and atmospheric pressure immersing in sequence; the vacuum immersing is performed at a pressure of <10 Pa and a temperature of room temperature for 1-48 h; the atmospheric pressure immersing is performed at a temperature of room temperature for 1-48 h; the settling solution includes an aqueous solution of one or a combination of more than one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate and acetic acid, and the concentration of the settling solution is 0.1-5 mol / L; the mass ratio of the carrier to the settling solution is (1:10)-(2:1); (3) sintering the carrier obtained in step (2) in air, holding after sintering and then cooling to below the boiling point of the active substance precursor to obtain a catalyst carrier with a catalyst active substance precursor film attached thereto; (4) reducing the catalyst carrier obtained in step (3) in situ in a reducing atmosphere to obtain a methanol reforming hydrogen production catalyst containing a CuO and Cu2O film; the reducing atmosphere is pure hydrogen or a mixture of methanol and water vapor, and the molar ratio of methanol to water vapor in the mixture is (2:1)-(1:2); the in-situ reduction temperature is 150-300°C, and the reduction time is 5-600 min.

2. The CuO and Cu20 containing thin film catalyst for hydrogen production by methanol reforming according to claim 1, characterized in that, the mass ratio of the carrier, the active substance and the auxiliary agent is (70-95):(4-20):(1-10).

3. The CuO and Cu20 containing thin film catalyst for hydrogen production by methanol reforming according to claim 1, characterized in that, the diameter of the Al2O3 beads is 0.5-30 mm; the Al2O3 beads are composed of Al2O3 particles with a diameter of 10-20 nm arranged in a certain order, so that the interior and surface of the beads form interconnected nanochannels with a pore size of less than 5 nm.

4. The method for producing a methanol reforming catalyst for hydrogen production containing a CuO and Cu2O thin film according to any one of claims 1 to 3, characterized by, the preparation steps are as follows: (1) dissolving the active substance and the auxiliary agent in deionized water-organic alcohol / acid respectively to form an organic alcohol / acid-metal salt solution; the organic alcohol / acid includes any one or a combination of more than one of methanol, formic acid, ethanol and propanol; (2) the carrier is immersed in the organic alcohol / acid-metal salt solution obtained in step (1), filtered, and then placed in a settling solution for soaking, filtering, and drying to obtain a carrier loaded with a precursor of an active substance; the precursor of the active substance is one or a combination of Cu2(OH)2SO4, Cu2(OH)2CO3, and Cu(CH3COO)2; The impregnation is vacuum impregnation and atmospheric pressure impregnation in sequence; the vacuum impregnation is performed at a pressure of < 10 Pa and a temperature of room temperature for 1-48 h; the atmospheric pressure impregnation is performed at a temperature of room temperature for 1-48 h; the settling solution comprises one or a combination of an aqueous solution of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and acetic acid; the concentration of the settling solution is 0.1-5 mol / L; and the mass ratio of the carrier to the settling solution is (1:10)-(2:1). (3) the carrier obtained in step (2) is sintered in air, cooled to below the boiling point of the precursor of the active substance, and then cooled to room temperature to obtain a catalyst carrier with a thin film of the precursor of the catalyst active substance attached thereto; (4) the catalyst carrier obtained in step (3) is reduced in situ in a reducing atmosphere to obtain a methanol reforming hydrogen production catalyst containing CuO and Cu2O thin films. The reducing atmosphere is pure hydrogen or a mixture of methanol and water vapor; the molar ratio of methanol to water vapor in the mixture is (2:1)-(1:2); the in-situ reduction temperature is 150-300°C; and the reduction time is 5-600 min.

5. The preparation method according to claim 4, characterized in that, The soluble metal solution corresponding to the active substance in step (1) comprises one or a combination of copper sulfate, copper nitrate, and copper chloride. The soluble metal solution corresponding to the auxiliary agent comprises one or a combination of cerium nitrate, cerium ammonium nitrate, cerium acetate, cerium sulfate, cerium ammonium sulfate, zirconium nitrate, zirconium acetate, zirconium sulfate, zirconium chloride, zinc nitrate, zinc acetate, zinc sulfate, chromium nitrate, chromium sulfate, and chromium chloride.

6. The preparation method according to claim 4, characterized in that, The total metal cation concentration in the organic alcohol / acid-metal salt solution in step (1) is 0.1-5 mol / L; the molar ratio of copper ions to auxiliary agent metal ions in the organic alcohol / acid-metal salt solution is (20:1)-(2:1); and the mass ratio of organic alcohol / acid to deionized water in the deionized water-organic alcohol / acid solution is (0:1)-(2:1).

7. The preparation method according to claim 4, characterized in that, The mass ratio of the carrier to the organic alcohol / acid-metal salt solution in step (2) is (1:10)-(2:1); and the drying temperature in step (2) is 60-90°C, and the drying time is 2.5-4.5 h.

8. The preparation method according to claim 4, characterized in that, The sintering in step (3) is performed at a temperature rising rate of 2-20°C / min, a sintering maximum temperature of 200-500°C, and a holding time of 5-300 min; and the cooling rate in step (3) is 2-20°C / min.

9. Use of a methanol reforming hydrogen catalyst according to any one of claims 1 to 3 or a methanol reforming hydrogen catalyst produced by a method according to any one of claims 4 to 8 in the methanol reforming for hydrogen production, characterized in that, The catalyst is used for the steam reforming of methanol, the partial oxidation reforming of methanol, or the cracking of methanol at 150-300°C.

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