Copper-zinc-aluminum catalytic material prepared by alkaline atmosphere ball milling method and application thereof

Abstract

The application discloses a copper-zinc-aluminum catalytic material prepared by a ball milling method in an alkaline atmosphere and application thereof, and belongs to the field of catalytic technology. The preparation method of the copper-zinc-aluminum catalytic material comprises the following steps: (1) mixing a copper powder, a zinc powder and an aluminum source to obtain a mixed powder, and adding the mixed powder into a ball milling tank provided with zirconium oxide ball milling beads; (2) after air in the ball milling tank is removed, alkaline mixed gas is filled into the ball milling tank, and the ball milling tank is placed into a ball mill; (3) after ball milling, the obtained precursor powder is dried; (4) the dried precursor powder is calcined to obtain a catalyst powder, the catalyst powder is mixed with graphite, and tabletting is performed to form a copper-zinc-aluminum catalytic material. The preparation process is simple, the preparation cost is relatively low, waste gas and waste water are not generated in the preparation process, high cost of environmental protection treatment is avoided, and the copper-zinc-aluminum catalytic material prepared has high activity and stability in a methanol water reforming hydrogen reaction.

Description

Technical Field

[0001] This invention relates to the field of catalysis technology, specifically to a copper-zinc-aluminum catalytic material prepared by ball milling under an alkaline atmosphere and its application. Background Technology

[0002] Methanol reforming for hydrogen production is a widely used method, primarily involving the reaction of methanol and water under specific temperature and pressure conditions, aided by a catalyst. Methanol reforming technology offers advantages such as compact equipment, simple operation, and high energy efficiency, making it promising for applications in mobile energy, industrial production, and energy storage. Copper-zinc-aluminum catalysts are commonly used in methanol reforming, mainly composed of oxides of copper, zinc, and aluminum. Copper exhibits excellent activation capabilities, while the addition of zinc and aluminum enhances the catalyst's structural stability. These catalysts not only possess high activity and selectivity but also offer relatively low cost, leading to their widespread application in industrial production.

[0003] There are many reports on copper, zinc and aluminum catalysts for methanol reforming to hydrogen. The author Didi Li (Nature Catalysis, 2022(5):99-108) prepared it by co-precipitation method, which is to dissolve copper nitrate and aluminum nitrate in deionized water, and add the precipitant dropwise to the solution at 60°C under vigorous stirring. The mixture is aged overnight and filtered, the precipitate is dried at 100°C for 12 hours, and finally the catalyst powder is calcined in static air at 450°C for 4 hours. The preparation process of this catalyst is complicated and requires the treatment of nitrogen-containing wastewater and waste gas, which leads to high cost. Based on the industrial Cu / ZnO / Al2O3 catalyst, author Zaizhe Cheng (Journal of Energy Chemistry, 2021, 63: 550-557) synthesized a series of CuZnAl-xMg catalysts with enhanced Cu-ZnO synergistic effect through magnesium modification. The study found that the incorporation of magnesium is beneficial to improving catalytic activity and catalyst stability. The catalyst is also prepared by using nitrate as raw material, adopting a co-precipitation method, aging, filtering the precipitate and washing it until the filtrate is neutral, and finally drying and calcining at 623K for 4h. It can be seen that the copper-zinc-aluminum catalyst also has the problems of complicated process and high cost.

[0004] In summary, the copper-zinc-aluminum catalysts for methanol reforming to hydrogen prepared by existing technologies all suffer from cumbersome processes and high costs. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a copper-zinc-aluminum catalytic material prepared by alkaline atmosphere ball milling and its application. This invention not only has a simple preparation process and low preparation cost, but also does not generate waste gas or wastewater during the preparation process, thus avoiding the high cost of environmental treatment. At the same time, the prepared copper-zinc-aluminum catalytic material exhibits high activity and stability in catalyzing the methanol-water reforming hydrogen production reaction.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A copper-zinc-aluminum catalytic material prepared by ball milling under an alkaline atmosphere, the preparation method of the copper-zinc-aluminum catalytic material includes the following steps:

[0008] (1) Mix copper powder, zinc powder and aluminum source to obtain mixed powder, and add the mixed powder to a grinding jar containing zirconia grinding beads.

[0009] (2) After removing the air from the ball mill jar, fill the ball mill jar with alkaline mixed gas, and then place the ball mill jar into a high-speed ball mill equipped with a heating and temperature control device;

[0010] (3) Control the reaction temperature of the ball mill jar at 80-100℃ and ball mill at 600-800rpm for 2-3h. After the reaction is completed, dry the obtained precursor powder.

[0011] (4) The dried precursor powder is transferred to a muffle furnace and calcined in an air atmosphere at 250-300℃ for 3-5 hours to obtain catalyst powder. After being mixed with graphite and pressed into tablets, copper-zinc-aluminum catalyst material can be obtained.

[0012] Furthermore, in step (1), after the copper powder, the zinc powder and the aluminum source are mixed, the atomic molar ratio of copper, zinc and aluminum in the mixed powder is 2-4:2:1.

[0013] Furthermore, in step (1), the aluminum source is selected from one or more of alumina, boehmite, bauxite, and aluminum hydroxide powder.

[0014] Furthermore, in step (1), the zirconia grinding balls comprise 50-70% of the total mass of grinding balls with a particle size of 2 mm, 20-30% of the total mass of grinding balls with a particle size of 4 mm, and 10-20% of the total mass of grinding balls with a particle size of 0.8 mm; the mass ratio of the mixed powder to the zirconia grinding balls is 1:3-5.

[0015] Furthermore, the grinding jar is an atmosphere-protected grinding jar or a vacuum grinding jar.

[0016] Furthermore, the grinding jar includes an inner liner, an inner liner cover, an outer liner, an outer cover, and a top cover; the inner liner and the inner liner cover are made of polytetrafluoroethylene (PTFE), and the inner liner cover is respectively provided with an air inlet and an air outlet composed of a one-way valve and a two-way valve. The inner liner and the inner liner cover are connected and sealed by threads and a sealing ring; the outer liner, the outer cover, and the top cover are made of 304 stainless steel, the top of the outer cover is through, the lower end of the outer cover is connected to the outer liner by threads, and the upper end of the outer cover is connected and sealed to the top cover by threads; the grinding jar can withstand a pressure range of 0-8 MPa.

[0017] Furthermore, in step (2), the alkaline mixed gas is composed of CO2, O2, NH3, and H2O. The molar ratio of CO2:O2:NH3:H2O in the alkaline mixed gas is 1:0.11-0.3:0.2-0.5:0.13-0.2, and the gas is introduced in the following order: CO2, O2, NH3, H2O.

[0018] Furthermore, in step (2), the amount of alkaline mixed gas introduced is based on a molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder of 2-4:1.

[0019] Furthermore, in step (3), the obtained precursor powder is dried at 110°C for 8 hours.

[0020] Furthermore, in step (4), the mass ratio of the catalyst powder to the graphite is 95-100:3; in the tableting process, the pressure is 10-12 MPa and the diameter of the molding die is 2-8 mm.

[0021] This invention also provides the application of the aforementioned copper-zinc-aluminum catalyst in the methanol-water reforming catalytic reaction for hydrogen production. The process conditions for this application are as follows: reaction temperature 180-260℃, pressure 0.1-2.5MPa, and feed mass hourly space velocity (WHSV) 0.1-1.0h. -1 In the H2O / CH3OH raw material reaction solution, CH3OH accounts for 50% by mass.

[0022] The beneficial effects of this invention are as follows:

[0023] (1) The copper-zinc-aluminum catalytic material of the present invention has the characteristics of simple process, convenient operation and low preparation cost.

[0024] (2) The precursor prepared by this invention forms extremely small green copper zinc ore or zinc malachite crystals, which reduces the particle size of copper species formed during roasting and improves the copper dispersion in the copper zinc aluminum catalyst. Therefore, the copper zinc aluminum catalyst has excellent activity in the low-temperature catalytic methanol-water reforming hydrogen production reaction. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the ball mill jar used in Example 1;

[0026] Figure 2 The image shows a SEM image of the precursor powder prepared in Example 1. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] Example 1

[0029] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0030] Ball milling is performed using a high-pressure resistant ball mill jar, such as... Figure 1 As shown, the grinding jar includes an inner liner, an inner liner cover, a metal outer liner, a metal outer cover, and a metal top cover. The inner liner and the inner liner cover are made of polytetrafluoroethylene (PTFE). The inner liner cover has an air inlet and an air outlet, each consisting of a one-way valve and a two-way valve. The inner liner and the inner liner cover are connected and sealed by threads and a sealing ring to form the PTFE inner liner. The PTFE inner liner is connected to the outside via the air inlet and the air outlet. The metal outer liner, the metal outer cover, and the metal top cover are made of 304 stainless steel. The top of the metal outer cover is through-hole. The lower end of the metal outer cover is connected to the metal outer liner by threads, and the upper end of the metal outer cover is connected and sealed to the metal top cover by threads. The metal top cover is designed for easy inflation and deflation. The metal outer cover and the metal outer liner can be connected and fixed to protect the PTFE inner liner first. After inflation or deflation, the metal top cover is then connected and sealed to the metal outer cover. The grinding jar can withstand a pressure range of 0-8 MPa.

[0031] (1) Weigh 3.79g of copper powder, 3.90g of zinc powder and 2.33g of aluminum hydroxide respectively and mix them into a mixed powder in a polytetrafluoroethylene inner liner. Add 24.01g of zirconia grinding beads with a particle size of 2mm, 10.0g of zirconia with a particle size of 4mm and 6.01g of zirconia with a particle size of 0.8mm. Cover the polytetrafluoroethylene inner liner with the lid and tighten it to seal. Put the polytetrafluoroethylene inner liner into the metal outer liner and put on the metal outer lid and tighten it.

[0032] (2) After removing the air from the polytetrafluoroethylene inner liner of the ball mill jar through the air outlet, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar through the air inlet to form an alkaline mixed gas, with the molar ratio of CO2:O2:NH3:H2O being 1:0.15:0.3:0.15. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. The metal top cover is screwed on, and then the ball mill jar is placed in a high-speed ball mill equipped with a heating and temperature control device.

[0033] (3) The temperature of the ball mill jar was raised to 85℃, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction, the obtained precursor powder was dried at 110℃ for 8 hours. Figure 2 The image shown is an SEM image of the precursor powder. From part A of the image, it can be observed that the crystal grains distributed in the precursor are extremely small, and from part B of the image, it can be observed that tiny plate-like crystals are present, which corresponds to the structural characteristics of chalcopyrite or zinc peacock crystals.

[0034] (4) The precursor powder obtained above is transferred to a muffle furnace and calcined in an air atmosphere at 255°C for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture is pressed into a 3mm mold under a pressure of 10MPa to obtain copper-zinc-aluminum catalyst material 1.

[0035] Example 2

[0036] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0037] (1) The same grinding jar as in Example 1 was used. 3.79g of copper powder, 3.90g of zinc powder, and 2.33g of aluminum hydroxide were weighed and mixed into a mixed powder in a polytetrafluoroethylene (PTFE) inner liner. 40.06g of zirconia grinding beads with a particle size of 4mm were added, and the PTFE inner liner was covered and tightened to seal. The PTFE inner jar was then placed inside the metal outer jar, and the metal outer cover was installed and tightened.

[0038] (2) After removing the air from the high-pressure ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar according to the molar ratio of CO2:O2:NH3:H2O of 1:0.15:0.3:0.15 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. The metal top cover is screwed on, and then the high-pressure ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0039] (3) The temperature of the ball mill jar was raised to 85°C, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0040] (4) The precursor obtained above was transferred to a muffle furnace and calcined at 255°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture was pressed into a 3mm mold under a pressure of 10MPa to obtain copper-zinc-aluminum catalyst material 2.

[0041] Example 3

[0042] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0043] (1) The grinding jar is the same as in Example 1. Weigh 3.79g of copper powder, 3.90g of zinc powder, and 2.33g of aluminum hydroxide to form a mixed powder and place it in a polytetrafluoroethylene (PTFE) inner liner. Add 24.01g of zirconia grinding balls with a particle size of 2mm, 10.0g of 4mm of particle size, and 6.01g of 0.8mm of particle size. Cover the PTFE inner liner with the lid and tighten it to seal. Place the PTFE inner liner into the metal outer liner and tighten the metal outer lid.

[0044] (2) After removing the air from the high-pressure ball mill jar, fill the inner liner of the ball mill jar with the alkaline mixed gas CO2:O2:NH3:H2O in sequence according to the molar ratio of the alkaline mixed gas CO2:O2:NH3:H2O of 1:0.15:0.3:0.15 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. Screw on the metal top cover and then put the high-pressure ball mill jar into the high-speed ball mill equipped with a heating and temperature control device.

[0045] (3) The temperature of the ball mill jar was raised to 60°C, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0046] (4) The precursor obtained above was transferred to a muffle furnace and calcined at 255°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture was pressed into tablets using a pressure of 10 MPa in a 3 mm mold to obtain copper-zinc-aluminum catalyst material 3.

[0047] Example 4

[0048] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0049] (1) The grinding jar is the same as in Example 1. Weigh 3.79g of copper powder, 3.90g of zinc powder, and 2.33g of aluminum hydroxide to form a mixed powder and place it in a polytetrafluoroethylene (PTFE) inner liner. Add 24.01g of zirconia grinding balls with a particle size of 2mm, 10.0g of 4mm of particle size, and 6.01g of 0.8mm of particle size. Cover the PTFE inner liner with the lid and tighten it to seal. Place the PTFE inner liner into the metal outer liner and tighten the metal outer lid.

[0050] (2) After removing the air from the high-pressure ball mill jar, CO2, O2 and H2O are sequentially introduced into the inner liner of the ball mill jar to form a mixed gas with a molar ratio of CO2:O2:H2O of 1:0.15:0.15. The molar ratio of (Cu+Zn):C atoms in the mixed gas and the mixed powder is 3:1. The metal top cover is screwed on, and then the high-pressure ball mill jar is placed in a high-speed ball mill equipped with a heating and temperature control device.

[0051] (3) The temperature of the ball mill jar was raised to 85°C, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0052] (4) The precursor obtained above was transferred to a muffle furnace and calcined at 255°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture was pressed into a 3mm mold under a pressure of 10MPa to obtain copper-zinc-aluminum catalyst material 4.

[0053] Example 5

[0054] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0055] (1) The grinding jar is the same as in Example 1. Weigh 3.79g of copper powder, 3.90g of zinc powder, and 2.33g of aluminum hydroxide to form a mixed powder and place it in a polytetrafluoroethylene (PTFE) inner liner. Add 24.01g of zirconia grinding balls with a particle size of 2mm, 10.0g of 4mm of particle size, and 6.01g of 0.8mm of particle size. Cover the PTFE inner liner with the lid and tighten it to seal. Place the PTFE inner liner into the metal outer liner and tighten the metal outer lid.

[0056] (2) After evacuating the air from the high-pressure ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar according to the molar ratio of CO2:O2:NH3:H2O of 1:0.15:0.3:0.15 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 1:1. The metal top cover is screwed on, and then the high-pressure ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0057] (3) The temperature of the ball mill jar was raised to 85°C, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0058] (4) The precursor obtained above is transferred to a muffle furnace and calcined at 255°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture is pressed into tablets using a pressure of 10 MPa in a 3 mm mold to obtain copper-zinc-aluminum catalyst material 5.

[0059] Example 6

[0060] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0061] (1) The grinding jar is the same as in Example 1. Weigh 2.35g of copper powder, 4.83g of zinc powder, and 2.88g of aluminum hydroxide to form a mixed powder and place it in a polytetrafluoroethylene (PTFE) inner liner. Add 24.01g of zirconia grinding balls with a particle size of 2mm, 10.0g of 4mm of particle size, and 6.01g of 0.8mm of particle size. Cover the PTFE inner liner with the jar and tighten the seal. Place the PTFE inner liner into the metal outer liner and tighten the metal outer cap.

[0062] (2) After removing the air from the high-pressure ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar according to the molar ratio of CO2:O2:NH3:H2O of 1:0.15:0.3:0.15 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. The metal top cover is screwed on, and then the high-pressure ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0063] (3) The temperature of the ball mill jar was raised to 85°C, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0064] (4) The precursor obtained above is transferred to a muffle furnace and calcined at 255°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture is pressed into tablets using a pressure of 10 MPa in a 3 mm mold to obtain copper-zinc-aluminum catalyst material 6.

[0065] Example 7

[0066] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0067] (1) The grinding jar is the same as in Example 1. Weigh 3.79g of copper powder, 3.90g of zinc powder, and 2.33g of aluminum hydroxide to form a mixed powder and place it in a polytetrafluoroethylene (PTFE) inner liner. Add 24.01g of zirconia grinding balls with a particle size of 2mm, 10.0g of 4mm of particle size, and 6.01g of 0.8mm of particle size. Cover the PTFE inner liner with the lid and tighten it to seal. Place the PTFE inner liner into the metal outer liner and tighten the metal outer lid.

[0068] (2) After removing the air from the high-pressure ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar according to the molar ratio of CO2:O2:NH3:H2O of 1:0.15:0.3:0.15 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. The metal top cover is screwed on, and then the high-pressure ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0069] (3) The temperature of the ball mill jar was raised to 85℃, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110℃ for 8 hours.

[0070] (4) The precursor obtained above is transferred to a muffle furnace and calcined at 350°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture is pressed into tablets using a pressure of 10 MPa in a 3 mm mold to obtain copper-zinc-aluminum catalyst material 7.

[0071] Example 8

[0072] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0073] (1) Weigh 4.78g of copper powder, 3.28g of zinc powder and 1.95g of aluminum hydroxide respectively, mix them into a mixed powder and put it into a ball mill jar under atmosphere protection. Add 24.01g of zirconia grinding balls with a particle size of 2mm, 10.0g of zirconia with a particle size of 4mm and 6.01g of zirconia with a particle size of 0.8mm.

[0074] (2) After evacuating the air from the atmosphere-protected ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar to form an alkaline mixed gas, with a molar ratio of CO2:O2:NH3:H2O of 1:0.15:0.3:0.15. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. Then the sealed atmosphere-protected ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0075] (3) The temperature of the ball mill jar was raised to 85°C, and the mixture was ball-milled at 800 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0076] (4) The precursor obtained above was transferred to a muffle furnace and calcined at 255°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture was pressed into tablets using a pressure of 10 MPa in a 3 mm mold to obtain copper-zinc-aluminum catalyst material 8.

[0077] Example 9

[0078] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0079] (1) Weigh 5.50g of copper powder, 2.83g of zinc powder and 1.69g of aluminum hydroxide respectively, mix them into a mixed powder and put them into a ball mill jar under atmosphere protection. Add 20.01g of zirconia grinding balls with a particle size of 2mm, 12.0g of zirconia with a particle size of 4mm and 8.01g of zirconia with a particle size of 0.8mm.

[0080] (2) After removing the air from the atmosphere-protected ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar according to the molar ratio of CO2:O2:NH3:H2O of 1:0.3:0.5:0.2 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. Then the sealed atmosphere-protected ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0081] (3) The temperature of the ball mill jar was raised to 80°C, and the mixture was ball-milled at 700 rpm for 2 hours. After the reaction was completed, the obtained precursor powder was dried at 110°C for 8 hours.

[0082] (4) The precursor obtained above is transferred to a muffle furnace and calcined at 300°C in air atmosphere for 3 hours to obtain catalyst powder. After weighing and mixing the catalyst powder and graphite at a mass ratio of 97:3, the mixture is pressed into a 3mm mold under a pressure of 10MPa to obtain copper-zinc-aluminum catalyst material 9.

[0083] Example 10

[0084] A method for preparing copper-zinc-aluminum catalytic materials by ball milling under an alkaline atmosphere includes the following steps:

[0085] (1) Weigh 3.79g of copper powder, 3.89g of zinc powder and 2.32g of aluminum hydroxide respectively, mix them into a mixed powder and put it into a vacuum ball mill jar. Add 28.01g of zirconia grinding balls with a particle size of 2mm, 8.0g of 4mm of particle size and 4.0g of 0.8mm of particle size.

[0086] (2) After removing the air from the atmosphere-protected ball mill jar, CO2, O2, NH3 and H2O gases are sequentially introduced into the inner liner of the ball mill jar according to the molar ratio of CO2:O2:NH3:H2O of 1:0.11:0.2:0.13 to form an alkaline mixed gas. The molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder is 3:1. Then the sealed atmosphere-protected ball mill jar is placed into a high-speed ball mill equipped with a heating and temperature control device.

[0087] (3) The temperature of the ball mill jar was raised to 100℃, and the mixture was ball milled at 600 rpm for 3 hours. After the reaction was completed, the obtained precursor powder was dried at 110℃ for 8 hours.

[0088] (4) The precursor obtained above was transferred to a muffle furnace and calcined at 250°C in air for 5 hours to obtain catalyst powder. The catalyst powder and graphite were weighed and mixed at a mass ratio of 97:3, and then pressed into a 3mm mold using a pressure of 10 MPa to obtain copper-zinc-aluminum catalyst material 10.

[0089] Application and efficacy verification of copper-zinc-aluminum catalytic materials:

[0090] In this invention, the catalytic activity was tested using a micro-fixed-bed reactor. The copper-zinc-aluminum catalyst was loaded with 5.0 g of material, and the inert bed was made of quartz sand. Before use, the catalyst was reduced in situ in the reactor using a hydrogen-nitrogen mixture with a hydrogen concentration of 5% at 270°C for 3 hours. After reduction, the temperature of the catalyst bed was lowered to 180°C, and a methanol-water mixture (50 wt% methanol) was pumped at a mass hourly space velocity (MHSV) of 0.1 h⁻¹. -1 0.3h -1 The methanol is introduced into a vaporizer, vaporized into methanol-water vapor, and then enters the catalyst bed for methanol-water reforming to produce hydrogen. When the reaction pressure reaches 0.5 MPa, gas chromatography is used for online analysis of the product tail gas and condensate. The area normalization method is used to quantitatively analyze H2, CO2, CO, and other byproducts in the product gas, and the CO selectivity is calculated. Liquid chromatography is used to analyze the methanol and water content in the condensate, and the methanol conversion rate is calculated. The results calculated for each set of examples are shown in Table 1.

[0091] Table 1 shows the test results of the performance of each group of copper-zinc-aluminum catalysts in the methanol-water reforming hydrogen production reaction.

[0092]

[0093] A comparison of the data from Examples 1 and 2 shows that Example 2 used only one type of milling ball, and the performance of the copper-zinc-aluminum catalyst prepared in Example 2 was significantly lower than that prepared in Example 1. Therefore, this invention can significantly improve the catalytic performance of copper-zinc-aluminum materials by setting different particle sizes and ratios of milling balls.

[0094] A comparison of the data from Examples 1 and 3 shows that the temperature control during the ball milling precursor preparation stage in Example 3 was different, leading to a significant decrease in the performance of the copper-zinc-aluminum catalyst prepared in Example 3. This indicates that suitable heating conditions during the ball milling reaction are a key factor affecting the preparation of copper-zinc-aluminum catalysts.

[0095] A comparison of the data from Examples 1 and 4 shows that no NH3 was introduced during the catalyst preparation process in Example 4, resulting in a catalyst with significantly lower activity than the one prepared in Example 1. This demonstrates that no reaction occurred between the copper, zinc, and aluminum raw materials prepared by the mixed gas without the introduction of NH3, thus the prepared copper-zinc-aluminum catalyst exhibits extremely low performance.

[0096] A comparison of the data from Examples 1 and 5 shows that in Example 5, the ratio of the alkaline mixed gas to the copper-zinc ratio in the mixed powder deviated from the range required by this invention during the catalyst preparation process. This resulted in a catalyst with lower activity than the catalyst prepared in Example 1. This indicates that the amount of alkaline mixed gas affects the degree of reaction between the copper, zinc, and aluminum raw materials, thereby affecting the performance of the catalyst.

[0097] A comparison of the data from Examples 1 and 6 shows that the amount of copper powder added during the catalyst preparation process in Example 6 was lower than the range required by this invention, resulting in a lower catalyst activity compared to the catalyst prepared in Example 1. This indicates that the catalytic performance of copper-zinc-aluminum catalysts prepared by reducing the proportion of copper source, deviating from the method of this invention, is reduced.

[0098] A comparison of the data from Examples 1 and 7 shows that in the catalyst preparation process of Example 7, the calcination temperature of the precursor was higher than the range required by this invention, resulting in lower catalyst activity compared to the catalyst prepared in Example 1. This indicates that increasing the calcination temperature of the precursor to prepare copper-zinc-aluminum catalysts, deviating from the methods of this invention, leads to a decrease in catalytic performance.

[0099] A comparison of the data from Examples 1 and 8 shows that, during the catalyst preparation process in Example 8, by appropriately increasing the ratio of the copper source within the scope of this invention, the catalyst prepared in Example 8 exhibited higher activity than the catalyst prepared in Example 1. This demonstrates that increasing the content of the active component within the required range is beneficial for improving the performance of the catalytic reaction.

[0100] A comparison of the data from Examples 1, 9, and 10 shows that, during the catalyst preparation process in Examples 9 and 10, the molar ratio of the mixed gas to copper, zinc, and aluminum was changed within the scope of this invention, resulting in catalysts with higher activity than the catalyst prepared in Example 1. This demonstrates that increasing the content of the active component within the required range is beneficial for improving the performance of the catalytic reaction.

[0101] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be defined by the claims.

Claims

1. A copper-zinc-aluminum catalytic material prepared by ball milling under an alkaline atmosphere, characterized in that, The preparation method of the copper-zinc-aluminum catalytic material includes the following steps: (1) Mix copper powder, zinc powder and aluminum source to obtain mixed powder, and add the mixed powder to a grinding jar containing zirconia grinding balls; the atomic molar ratio of copper, zinc and aluminum in the mixed powder is 2-4:2:1; in the zirconia grinding balls, grinding balls with a particle size of 2 mm account for 50-70% of the total grinding ball mass, grinding balls with a particle size of 4 mm account for 20-30% of the total grinding ball mass, and grinding balls with a particle size of 0.8 mm account for 10-20% of the total grinding ball mass; the mass ratio of the mixed powder to the zirconia grinding balls is 1:3-5; (2) After removing the air from the ball mill jar, the alkaline mixed gas is introduced into the ball mill jar, and then the ball mill jar is placed into the ball mill. The alkaline mixed gas is composed of CO2, O2, NH3, and H2O. The molar ratio of CO2:O2:NH3:H2O in the alkaline mixed gas is 1:0.11-0.3:0.2-0.5:0.13-0.2, and the gas is introduced in the following order: CO2, O2, NH3, H2O. The amount of alkaline mixed gas introduced is based on the molar ratio of (Cu+Zn):C atoms in the alkaline mixed gas and the mixed powder being 2-4:

1. (3) Control the reaction temperature of the ball mill jar at 80-100℃, and ball mill the reaction at 600-800 rpm for 2-3 hours. After the reaction is completed, dry the obtained precursor powder. (4) The dried precursor powder is calcined in air at 250-300℃ for 3-5 hours to obtain catalyst powder. After being mixed with graphite and pressed into tablets, copper-zinc-aluminum catalyst material can be obtained. The mass ratio of the catalyst powder to the graphite is 95-100:

3. In the tablet pressing process, the pressure is 10-12MPa and the diameter of the molding die is 2-8mm.

2. The copper-zinc-aluminum catalytic material prepared by alkaline atmosphere ball milling according to claim 1, characterized in that: In step (1), the aluminum source is selected from one or more of alumina, boehmite, bauxite, and aluminum hydroxide powder.

3. The copper-zinc-aluminum catalytic material prepared by alkaline atmosphere ball milling according to claim 1, characterized in that: The grinding jar is an atmosphere-protected grinding jar.

4. The copper-zinc-aluminum catalytic material prepared by alkaline atmosphere ball milling according to claim 1, characterized in that: The grinding jar includes an inner liner, an inner liner cover, an outer liner, an outer cover, and a top cover. The inner liner and the inner liner cover are made of polytetrafluoroethylene (PTFE). The inner liner cover is provided with an air inlet and an air outlet, each consisting of a one-way valve and a two-way valve. The inner liner and the inner liner cover are connected and sealed by threads and a sealing ring. The outer liner, the outer cover, and the top cover are made of 304 stainless steel. The top of the outer cover is through-hole. The lower end of the outer cover is connected to the outer liner by threads, and the upper end of the outer cover is connected and sealed to the top cover by threads. The grinding jar can withstand pressures ranging from 0 to 8 MPa.

5. The application of the copper-zinc-aluminum catalyst material according to any one of claims 1-4 in the catalytic reaction process of methanol-water reforming to produce hydrogen, wherein the process conditions for the application are as follows: reaction temperature of 180-260℃, pressure of 0.1-2.5MPa, and feed mass hourly space velocity of 0.1-1.0h. -1 In the H2O / CH3OH raw material reaction solution, CH3OH accounts for 50% by mass.

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