A metal catalyst, its preparation method and application

Abstract

This invention relates to the field of catalysts, specifically disclosing a metal catalyst comprising a composite support and a metal supported on the composite support. The composite support is composed of a first support and a second support. The key feature is that the affinity between the first support and the metal is stronger than that between the second support and the metal, and the first support is a nanoscale support. The metal catalyst provided by this invention selects a first support with a stronger affinity for the metal than the second support, resulting in a potential energy difference between the metal and the first and second supports. This creates high-potential-energy regions and a low-potential-energy region. The metal spontaneously transfers from the high-potential-energy region to the low-potential-energy region and remains firmly stable in the low-potential-energy region, forming a metastable state. Therefore, the metal catalyst exhibits good stability and resistance to sintering.

Description

[0001] This invention belongs to the field of catalysts, and more specifically, relates to a metal catalyst, its preparation method, and its application. Background Technology

[0002] Catalysts, as the foundation of the chemical industry, play a crucial role in modern chemical production. Among them, metal catalysts are widely used due to their advantages such as simple preparation processes, low cost, high activity, and high selectivity. When the size of metal particles reaches the nanometer scale or even smaller, the atomic utilization rate of the metal can be improved, and even the size effect of the material can be used to enhance the catalytic activity of the metal catalyst. However, the smaller the particle size of the metal, the greater the surface energy, the lower the stability, and the more prone the metal particles are to agglomeration, especially at higher temperatures. Sintering of metal catalysts is a major cause of catalyst deactivation. Maintaining high dispersibility while preserving catalyst activity is a challenge in the field of catalysis. The preparation of metal catalysts with both high activity and high thermal stability is an important research topic in the chemical industry.

[0003] In particular, many important industrial catalytic processes, such as propane dehydrogenation, methane-carbon dioxide reforming, and catalytic reforming, involve high-temperature catalytic reactions often exceeding 500°C. This high temperature sintering of metal catalysts can easily lead to rapid deactivation, severely limiting their practical application in these fields. Therefore, developing bifunctional metal catalytic systems that combine high catalytic activity with high-temperature resistance to sintering has always been a pressing scientific challenge in the field of catalysis and a key factor for breakthroughs in its industrial applications. Summary of the Invention

[0004] The present invention aims to overcome at least one defect (deficiency) of the prior art and provide a metal catalyst, its preparation method and application, in order to solve the technical problem that existing metal catalysts cannot simultaneously possess high catalytic activity and high-temperature anti-sintering performance in high-temperature catalytic reactions.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A metal catalyst comprising a composite support and a metal supported on the composite support, wherein the composite support is composed of a first support and a second support, wherein the affinity between the first support and the metal is greater than that between the second support and the metal, and wherein the first support is a nanoscale support.

[0007] In this invention, by selecting a first support with a stronger affinity for the metal than a second support, a potential energy difference exists between the metal and the first and second supports, thus forming a low-potential energy region and a high-potential energy region. The metal will spontaneously transfer from the high-potential energy region to the low-potential energy region and firmly stabilize in the low-potential energy region, forming a metastable state. As a result, the metal catalyst has good stability, good anti-sintering ability, high catalytic activity, and good selectivity.

[0008] In this invention, the first support is the main support component. The reason for choosing a composite support consisting of a first support and a second support is to allow the metal to selectively settle on the first support. The first support has a strong affinity for the metal, thus enabling selective metal placement. If only one support is used, the metal is directly loaded onto it, leading to metal particle aggregation and uneven size, as well as metal migration and catalyst instability. Furthermore, during high-temperature catalytic reactions, the metal particles gradually grow larger as the reaction progresses, severely reducing the catalyst's cycle performance. However, with two supports, the first support is uniformly dispersed on the second support, allowing the metal to settle on the first support, which then fixes the metal in place. The metal will not migrate and is more likely to form uniformly sized metal particles. Therefore, this invention uses a composite support consisting of a first support and a second support, enabling selective metal placement on the first support. Using only one support would not achieve the desired technical effect.

[0009] Further, the metal is at least one selected from Fe, Co, Cu, Ni, Bi, Zn, Pt, Sn, Ir, Rh, or Pd.

[0010] In this invention, all selected metals are active metals, which can improve the catalytic performance of catalysts when used to prepare catalysts for high-temperature catalytic reactions.

[0011] Furthermore, the first carrier is TiO2 or ZrO. 2、 At least one of MnO2.

[0012] Furthermore, the second support is at least one of SiO2, Al2O3, molecular sieve and montmorillonite, and the properties of these supports, such as pore surface area, meet the loading requirements.

[0013] In this invention, the first support is selected as at least one of TiO2, ZrO2, and MnO2, and the second support is selected as at least one of SiO2, Al2O3, molecular sieve, and montmorillonite because the above-mentioned active metals have a stronger affinity for TiO2, ZrO2, or MnO2 than the active metals have an affinity for SiO2, Al2O3, molecular sieve, and montmorillonite, thereby creating a potential energy difference between the metals on the first and second supports.

[0014] Furthermore, the mass ratio of the first carrier to the second carrier is (1-20):100.

[0015] In this invention, the mass ratio of the first carrier to the second carrier (1-20):100 is chosen because if there is too little first carrier, on the one hand, the metal will aggregate excessively, resulting in larger metal particle size, and on the other hand, the metal will be directly distributed on the second carrier and will not exert the effect that the first carrier should have; while if there is too much first carrier, on the one hand, the metal will be excessively dispersed, resulting in smaller metal particle size, and on the other hand, the second carrier will directly encapsulate the metal particles, causing the catalyst to lose its activity.

[0016] Furthermore, the loading of the metal is 0.01 to 10 wt.% based on the mass of the metal catalyst.

[0017] In this invention, the metal loading is selected to be 0.01 to 10 wt.% because when the metal loading is too low, the catalyst activity disappears; when the metal loading is too high, on the one hand, it will cause excessive metal aggregation, and on the other hand, the cost of using precious metals will increase.

[0018] A second aspect of the present invention provides a method for preparing the above-mentioned metal catalyst, comprising the following steps:

[0019] S1. Add the first carrier to the solvent and stir evenly at room temperature. Then add the second carrier and stir evenly for 2-8 hours. Remove the solvent and dry overnight at 60-120℃. Then calcine at 550℃-700℃ for 2-6 hours. After cooling, compress and sieve the tablets to obtain composite carrier particles for later use. Preferably, the composite carrier particles are 80-120 mesh.

[0020] S2. Dissolve at least one metal salt in a solvent and mix thoroughly to form a mixed solution. Impregnate the composite carrier particles prepared in step S1 in the mixed solution, sonicate for 0.5-1 h, dry overnight at 60-120℃, then calcine at 300-850℃ for 1.5-3 h, and then reduce in a hydrogen-argon mixed atmosphere at 550℃-850℃ for 2-4 h.

[0021] Further, the solvent in step S1 is at least one of water, ethanol, acetone, isopropanol, ethyl acetate, isobutanol, benzene, petroleum ether, and toluene, and the solvent in step S2 is hydrochloric acid and / or deionized water.

[0022] A third aspect of the invention provides the application of the aforementioned metal catalyst, wherein the metal catalyst is used in one of a propane dehydrogenation reaction, a methane-carbon dioxide reforming reaction, or a catalytic reforming reaction.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The metal catalyst provided by the present invention selects the first support to have a stronger affinity with the metal than the second support to have a stronger affinity with the metal, so that there is a potential energy difference between the metal on the first support and the second support, thereby forming a low potential energy region and a high potential energy region. The metal will spontaneously transfer from the high potential energy region to the low potential energy region and firmly stabilize in the low potential energy region to form a metastable state. Thus, the metal catalyst has good stability and good anti-sintering ability. At the same time, when the catalyst is a multi-metal catalyst, the metal spontaneously transfers to the first support region, making it easier for the multi-metal catalyst to form an alloy catalyst with good catalytic performance.

[0025] (2) The metal catalyst prepared by the present invention has good catalytic activity, high selectivity and low carbon deposition selectivity when used in high temperature catalytic reactions. Attached Figure Description

[0026] Figure 1a The image is a transmission electron microscope image obtained after the propane dehydrogenation reaction of metal catalyst A1 for 180 min.

[0027] Figure 1b The figure shows the particle size statistics of metal catalyst A1 after propane dehydrogenation reaction for 180 min.

[0028] Figure 2a The image is a transmission electron microscope image obtained after the propane dehydrogenation reaction of metal catalyst B1 for 180 min.

[0029] Figure 2b The figure shows the particle size statistics of metal catalyst B1 after propane dehydrogenation reaction for 180 min.

[0030] Figure 3a Transmission electron micrograph of metal catalyst A5 after methane-carbon dioxide reforming reaction for 180 min.

[0031] Figure 3b The figure shows the particle size distribution of metal catalyst A5 after a methane-carbon dioxide reforming reaction for 180 min. Figure 4a Transmission electron micrograph of metal catalyst B5 after methane-carbon dioxide reforming reaction for 180 min.

[0032] Figure 4b The particle size distribution of metal catalyst B5 after methane-carbon dioxide reforming reaction for 180 min is shown in the figure. Detailed Implementation

[0033] To enable those skilled in the art to better understand this solution, the following detailed description is provided in conjunction with specific embodiments. Unless otherwise specified, the process methods used in the embodiments are conventional methods; and unless otherwise specified, the materials used are commercially available.

[0034] Example

[0035] Example 1

[0036] S1. Add 0.41g of nano TiO2 (3-5nm) to 14.25g of ethanol and stir evenly at room temperature. Then add 5g of SiO2 powder and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then calcine at 600℃ for 2h. After cooling, compress and sieve to obtain 80-120 mesh composite carrier particles for later use.

[0037] S2. Dissolve 1.32g H2Cl6Pt·6H2O (10mgPt / 1g) and 0.068g SnCl4·5H2O in 0.15g HCl, then add 3.4g deionized water to obtain a mixed solution. Impregnate the support prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then calcine at 300℃ for 1.5h, and finally reduce in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst A1.

[0038] Example 2

[0039] S1. Add 0.2g of nano TiO2 (3-5nm) to 10.4g of ethanol and stir evenly at room temperature. Then add 5g of montmorillonite and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then calcine at 600℃ for 2h. After cooling, compress and sieve the tablets to obtain 80-120 mesh composite carrier particles for later use.

[0040] S2. Dissolve 1.11g H2Cl6Pt·6H2O (10mgPt / 1g) and 0.085g SnCl4·5H2O in 0.15g HCl, then add 3.4g deionized water to obtain a mixed solution. Impregnate the composite support particles prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then calcine at 300℃ for 1.5h, and finally reduce in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst A2.

[0041] Example 3

[0042] S1. Add 0.33g of nano TiO2 (3-5nm) to 13.2g of ethanol and stir evenly at room temperature. Then add 5g of SiO2 powder and stir evenly for 2h. Evaporate the ethanol and dry in an oven at 60℃ overnight. Then calcine at 550℃ for 2h. After cooling, compress and sieve to obtain 80-120 mesh composite carrier particles for later use.

[0043] S2, 0.404g Fe(NO3)3·9H2O and 0.291g Co(NO3)3·6H2O were dissolved in 3.88g deionized water to obtain a mixed solution. The composite support particles prepared in step S1 were impregnated in the mixed solution, sonicated for 0.5h, dried overnight in an oven at 80℃, calcined at 600℃ for 2h, and finally reduced in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst A3.

[0044] Example 4

[0045] S1. Add 0.88g of nano TiO2 (3-5nm) to 22g of ethanol and stir evenly at room temperature. Then add 5g of SiO2 powder and stir evenly for 8h. Evaporate the ethanol and dry in an oven at 120℃ overnight. Then calcine at 700℃ for 6h. After cooling, press and sieve the tablets to obtain 80-120 mesh composite carrier particles for later use.

[0046] S2, 0.148g Fe(NO3)3·9H2O and 0.121g Co(NO3)3·6H2O were dissolved in 4.31g deionized water to obtain a mixed solution. The composite support particles prepared in step S1 were impregnated in the mixed solution, sonicated for 0.5h, dried overnight in an oven at 80℃, calcined at 600℃ for 2h, and finally reduced in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst A4.

[0047] Example 5

[0048] S1. Add 0.65g of nano ZrO2 (5-10nm) to 18g of ethanol and stir evenly at room temperature. Then add 5g of SBA-15 molecular sieve and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then calcine at 600℃ for 2h. After cooling, compress and sieve to obtain 80-120 mesh composite carrier particles for later use.

[0049] S1. Dissolve 1.64g NiCl3·6H2O in 3.23g deionized water and mix thoroughly to obtain a mixed solution. Impregnate the composite support particles prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then calcine at 800℃ for 2h, and finally reduce in a hydrogen-argon mixed atmosphere at 800℃ for 2h to obtain metal catalyst A5.

[0050] Example 6

[0051] S1. Add 0.57g of nano MnO2 (6nm) to 17g of ethanol and stir evenly at room temperature. Then add 5g of Al2O3 powder and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then calcine at 600℃ for 2h. After cooling, compress and sieve to obtain 80-120 mesh composite carrier particles for later use.

[0052] S2. Add 1.32g H2Cl6Pt·6H2O (10mgPt / 1g) to 4.77g deionized water to obtain a mixed solution. Impregnate the support prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then calcine at 300℃ for 1.5h, and finally reduce in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst A6.

[0053] Comparative Example

[0054] It should be noted that Comparative Examples 1-4 refer to Example 1, Comparative Examples 5-8 refer to Example 5, and Comparative Examples 9-10 refer to Example 6.

[0055] Comparative Example 1

[0056] 1.32 g H2Cl6Pt·6H2O (10 mg Pt / 1 g) and 0.068 g SnCl4·5H2O were dissolved in 0.15 g HCl, and then 3.4 g deionized water was added. After mixing thoroughly, a mixed solution was obtained. Then, 5 g SiO2 powder was immersed in the mixed solution and sonicated for 0.5 h. After drying in an oven at 80 °C overnight, it was calcined at 300 °C for 1.5 h. Finally, it was reduced in a hydrogen-argon mixed atmosphere at 600 °C for 2 h to obtain B1.

[0057] Comparative Example 2

[0058] Following the preparation method of Comparative Example 1, except that SiO2 was replaced with TiO2, metal catalyst B2 was obtained.

[0059] Comparative Example 3

[0060] S1. Add 0.41g of nano TiO2 (3-5nm) to 14.25g of ethanol and stir evenly at room temperature. Then add 5g of CeO2 powder and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then calcine at 600℃ for 2h. After cooling, compress and sieve to obtain 80-120 mesh composite carrier particles for later use.

[0061] S2. Dissolve 1.32g H2Cl6Pt·6H2O (10mgPt / 1g) and 0.068g SnCl4·5H2O in 0.15g HCl, then add 3.4g deionized water to obtain a mixed solution. Impregnate the composite support particles prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then calcine at 300℃ for 1.5h, and finally reduce in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst B3.

[0062] Comparative Example 4

[0063] S1. Add 0.39g of nano Al2O3 (3-5nm) to 14.25g of ethanol and stir evenly at room temperature. Then add 5g of SiO2 powder and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then oxidize and decompose at 600℃ for 2h. After cooling, compress and sieve the tablets. Take 80-120 mesh particles as carriers for later use.

[0064] S2. Dissolve 1.32g H2Cl6Pt·6H2O (10mgPt / 1g) and 0.068g SnCl4·5H2O in 0.15g HCl, then add 3.4g deionized water to obtain a mixed solution. Impregnate the support prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then oxidize and decompose at 300℃ for 1.5h, and finally reduce in a hydrogen-argon mixed atmosphere at 600℃ for 2h to obtain metal catalyst B3.

[0065] Comparative Example 5

[0066] 1.64 g of NiCl3·6H2O was dissolved in 3.23 g of deionized water and mixed thoroughly to form a mixed solution. Then, 5 g of SBA-15 molecular sieve was immersed in the mixed solution, sonicated for 0.5 h, dried overnight in an oven at 80 °C, calcined at 800 °C for 2 h, and finally reduced in a hydrogen-argon mixed atmosphere at 800 °C for 2 h to obtain metal catalyst B5.

[0067] Comparative Example 6

[0068] Referring to Comparative Example 5, the only difference is that the SBA-15 molecular sieve was replaced with ZrO2, resulting in metal catalyst B6.

[0069] Comparative Example 7

[0070] S1. Add 0.65g of nano ZrO2 (5-10nm) to 18g of ethanol and stir evenly at room temperature. Then add 0.5g of SBA-15 molecular sieve and stir evenly for 4h. Evaporate the ethanol and dry in an oven at 80℃ overnight. Then calcine at 600℃ for 2h. After cooling, compress and sieve to obtain 80-120 mesh composite carrier particles for later use.

[0071] S2. Dissolve 1.64g NiCl3·6H2O in 3.23g deionized water and mix thoroughly to obtain a mixed solution. Impregnate the composite support particles prepared in step S1 in the mixed solution, sonicate for 0.5h, dry in an oven at 80℃ overnight, then calcine at 800℃ for 2h, and finally reduce in a hydrogen-argon mixed atmosphere at 800℃ for 2h to obtain metal catalyst B7.

[0072] Comparative Example 8

[0073] Referring to Comparative Example 7, the only difference from Comparative Example 7 is that 3.5g ZrO2 (5-10nm) was replaced with 0.1g ZrO2 (5-10nm).

[0074] Comparative Example 9

[0075] 1.32 g of H₂Cl₆Pt·₆H₂O (10 mg Pt / 1 g) was added to 4.77 g of deionized water and mixed thoroughly to form a mixed solution. Then, 5 g of Al₂O₃ was impregnated in the mixed solution, sonicated for 0.5 h, dried overnight in an oven at 80 °C, calcined at 300 °C for 1.5 h, and finally reduced for 2 h in a hydrogen-argon mixed atmosphere at 600 °C to obtain metal catalyst B9.

[0076] Comparative Example 10

[0077] Referring to Comparative Example 9, the only difference from Comparative Example 9 is that Al2O3 was replaced with MnO2 to obtain the metal catalyst B10.

[0078] Application examples

[0079] Application Example 1 and Application Comparative Examples 1-4

[0080] Application Examples 1 and Comparative Examples 1-4 respectively used the metal catalyst A1 prepared in Example 1 and the metal catalysts B1-B4 prepared in Comparative Examples 1-4 in the propane dehydrogenation reaction, wherein the reaction temperature was 600℃ and the propane space velocity was 3.9 h⁻¹. -1 The raw material was pure propane, and the propane dehydrogenation data were recorded in Table 1.

[0081] Table 1. Propane dehydrogenation results of Application Example 1 and Comparative Examples 1-4

[0082]

[0083] As shown in Table 1, the metal catalyst A1 prepared in Example 1 exhibits high methane conversion rate, high initial C3H6 selectivity, and low carbon deposition selectivity in the propane dehydrogenation reaction, indicating that the metal catalyst prepared in this invention has high catalytic activity and good anti-sintering performance.

[0084] Comparing the data from Application Example 1, Application Comparative Example 1, and Application Comparative Example 2, it can be seen that when the metal catalyst has only one support, the methane conversion rate of the prepared metal catalyst is much lower than that of the metal catalyst prepared with two supports when used in the propane dehydrogenation reaction. The initial C3H6 selectivity is low, while the carbon deposition selectivity is high. This indicates that the metal catalyst prepared by the present invention using two supports has higher catalytic activity and better anti-sintering performance than the metal catalyst with only one support.

[0085] As can be seen from the descriptions of Comparative Example 1, Comparative Example 3, and Comparative Example 4, when both the first and second supports are supports with strong metal affinity or both are supports with weak metal affinity, the methane conversion rate of the prepared metal catalyst is much lower than that of the metal catalyst prepared with the two supports when used in the propane dehydrogenation reaction. The initial C3H6 selectivity is also lower, and the carbon deposition selectivity is much higher. This indicates that the metal catalyst prepared by using two supports with different metal affinity has high catalytic activity and good anti-sintering performance.

[0086] Application Example 2 and Application Comparative Examples 5-8

[0087] Application Examples 2 and Comparative Examples 5-8 involve using metal catalyst A5 prepared in Example 5 and metal catalysts B5-B8 prepared in Comparative Examples 5-8, respectively, for methane-carbon dioxide reforming reactions. The reaction temperature was 850°C and the gas hourly space velocity (GHSV) was 24000 mL / h. -1 g -1 The volume ratio of CH4:CO2:Ar was 1:1:3, and the data of methane-carbon dioxide reforming were recorded in Table 2.

[0088] Table 2: Results of methane-carbon dioxide reforming in Application Examples 2 and Comparative Examples 5-8

[0089]

[0090] As shown in Table 2, the metal catalyst A1 prepared in Example 5 has a high initial CH4 / CO2 conversion rate and a high initial H2 / CO selectivity in the methane-carbon dioxide reforming reaction, but a very low carbon deposition selectivity. This indicates that the metal catalyst prepared in this invention has high catalytic activity and good anti-sintering performance.

[0091] Comparing the data from Application Example 2 and Application Comparative Examples 5-6, it can be seen that when the metal catalyst has only one support, the initial CH4 / CO2 conversion rate (%) of the prepared metal catalyst is much lower than that of the metal catalyst prepared with two supports when used in methane carbon dioxide reforming. The initial C3H6 selectivity is low, while the carbon deposition selectivity is high. This indicates that the metal catalyst prepared by the present invention using two supports has higher catalytic activity and better anti-sintering performance than the metal catalyst with only one support.

[0092] Comparing the data from Application Example 2 and Application Comparative Examples 7-8, it can be seen that the mass ratio of the first support to the second support is no longer within the range of the present invention. When the first support is too small, on the one hand, the metal will excessively aggregate, resulting in larger metal particle size; on the other hand, the metal directly distributed on the second support will not exert the effect that the first support should have. Its initial CH4 / CO2 conversion rate and initial H2 / CO selectivity are much lower than those of Application Comparative Example 2, while the carbon deposition selectivity is much higher. When the first support is too large, on the one hand, the metal will be excessively dispersed, resulting in smaller metal particle size; on the other hand, the second support directly encapsulates the metal particles, causing the catalyst to lose its activity. Its initial CH4 / CO2 conversion rate and initial H2 / CO selectivity are also much lower than those of Application Comparative Example 2, while the carbon deposition selectivity is much higher.

[0093] Application Example 3 and Application Comparative Examples 9-10

[0094] Application Examples 3 and Comparative Examples 9-10 involve using metal catalysts A6 and B9-B10, respectively, prepared using the methods described in Example 6 and Comparative Examples 9-10, for catalytic reforming reactions. The reaction temperature was 500°C and the space velocity was 1 h⁻¹. -1 The raw material was C6, and the data of catalytic reforming after the reaction were recorded in Table 3.

[0095] Table 3: Catalytic reforming results of Application Example 3 and Comparative Examples 9-10

[0096]

[0097] As shown in Table 3, the metal catalyst A6 prepared in Example 6 exhibits high C6 conversion, high aromatic selectivity, and very low carbon deposition selectivity in catalytic reforming reactions, indicating that the metal catalyst prepared in this invention has high catalytic activity and good anti-sintering performance.

[0098] Comparing the data from Application Example 3 and Application Comparative Examples 9-10, it can be seen that when the metal catalyst has only one support, the prepared metal catalyst has a much lower C6 conversion rate and aromatic selectivity than the metal catalyst prepared with two supports, but a much higher carbon deposition selectivity. This indicates that the metal catalyst prepared by the present invention using two supports has higher catalytic activity and better anti-sintering performance than the metal catalyst with only one support.

[0099] Test case

[0100] Transmission electron microscopy images and particle size analysis were performed on the metal catalysts of Application Example 1 and Application Comparative Example 1, as well as Application Example 5 and Application Comparative Example 5, after reacting for 180 min. Figures 1a-4b As shown.

[0101] Depend on Figures 1a-2b It can be seen that after propane dehydrogenation reaction for 180 min in Application Example 1 and Application Comparative Example 1, the average particle size of the metal catalyst with only one support is much larger than that of the metal catalyst with two supports. This indicates that the metal catalyst prepared by the present invention has good stability and good anti-sintering performance.

[0102] Depend on Figures 3a-4b It can be seen that after methane-carbon dioxide reforming reaction for 180 min in Application Example 2 and Application Comparative Example 5, the average particle size of the metal catalyst with only one support is much larger than that of the metal catalyst with two supports. This also shows that the metal catalyst prepared by the present invention has good stability and good anti-sintering performance.

[0103] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A metal catalyst, said metal catalyst comprising a composite support and a metal supported on the composite support, said composite support being composed of a first support and a second support, characterized in that, The first carrier has a stronger affinity for the metal than the second carrier. The first carrier is a nanoscale carrier, and the metal is at least one selected from Fe, Co, Cu, Ni, Zn, Pt, Sn, Ir, Rh, and Pd. The first carrier is TiO2 or ZrO. 2、 At least one of MnO2, wherein the mass ratio of the first support to the second support is (1~20):100, and the metal catalyst is prepared by a method comprising the following steps: S1. Add the first carrier to the solvent and stir evenly at room temperature. Then add the second carrier and stir evenly for 2-8 hours. Remove the solvent and dry overnight at 60-120℃. Then calcine at 550-700℃ for 2-6 hours. After cooling, compress and sieve the tablets to obtain the composite carrier particles for later use. S2. Dissolve at least one metal salt in a solvent and mix thoroughly to form a mixed solution. Impregnate the composite carrier particles prepared in step S1 in the mixed solution, sonicate for 0.5-1 h, dry overnight at 60-120°C, then calcine at 300-850°C for 1.5-3 h, and then reduce in a hydrogen-argon mixed atmosphere at 550-850°C for 2-4 h.

2. The metal catalyst according to claim 1, characterized in that, The second carrier is at least one of SiO2, Al2O3, molecular sieve and montmorillonite.

3. The metal catalyst according to claim 1, characterized in that, The loading of the metal is 0.01 to 10 wt., based on the mass of the metal catalyst.

4. The metal catalyst according to claim 1, characterized in that, The solvent in step S1 is at least one of water, ethanol, acetone, isopropanol, ethyl acetate, isobutanol, benzene, petroleum ether, and toluene, and the solvent in step S2 is hydrochloric acid and / or deionized water.

5. The application of a metal catalyst as described in any one of claims 1-4, characterized in that, The metal catalyst is used in propane dehydrogenation or methane-carbon dioxide reforming.

6. The application of a metal catalyst as described in any one of claims 1-4, characterized in that, The metal catalyst is used in the catalytic reforming reaction.

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