A highly stable noble metal-based catalyst based on strong metal-support interaction, a preparation method thereof, and its application in catalytic hydrogenation of carbon dioxide to methanol

Abstract

The present invention discloses a highly stable noble metal-based catalyst based on strong metal-carrier interaction, a preparation method, and its application in the catalytic hydrogenation of carbon dioxide to methanol. The method comprises mixing a dispersion containing a noble metal precursor and a metal oxide carrier with an alkali metal salt, then adding a hydrazine hydrate solution until the mixed solution turns gray-brown, and then evaporating the mixed solution to dryness and calcining. The present invention utilizes the bridge charge transfer effect of the alkali metal element to enhance the transfer rate of charge balance between the noble metal nanoparticles and the metal oxide carrier in the supported noble metal-based catalyst, thereby accelerating the induction of the metal oxide carrier to migrate and overflow to the surface of the noble metal nanoparticles under a high-pressure reducing atmosphere and forming a thin layer coating structure on the surface of the noble metal nanoparticles, thereby improving the stability and anti-sintering performance of the noble metal active center in the high-pressure reducing atmosphere, inhibiting the agglomeration and deactivation of the nanoparticles, and being able to achieve a CO2 conversion efficiency greater than 6%, a product methanol selectivity greater than 75%, and stable operation for more than 100 hours.

Description

Technical Field

[0001] The present invention belongs to the technical field of air pollution control, and particularly relates to a highly stable noble metal-based catalyst based on strong interaction between metal carriers, a preparation method thereof, and application thereof in catalytic hydrogenation of carbon dioxide to produce methanol. Background Art

[0002] With the increasing severity of global climate change and the energy crisis, converting excess CO2 in the atmosphere into usable carbon resources is a necessary path for humanity to achieve carbon neutrality and practice sustainable development. Among the numerous CO2 resource utilization technologies, thermodynamic CO2 hydrogenation technology has received extensive research and attention due to its advantages such as controllable conditions and ease of operation. Converting CO2 into high-energy-density fuels and high-value-added carbon products through hydrogenation reduction technology is one of the important ways to reduce CO2 concentration in the atmosphere, store intermittent renewable energy, and achieve carbon neutrality. Converting captured and pre-concentrated CO2 into high-value-added products such as methanol and dimethyl ether through a catalytic hydrogenation reduction process can not only effectively control the greenhouse effect caused by excessive CO2 emissions, but also help alleviate the energy crisis caused by the shortage of fossil energy.

[0003] Supported noble metal-based catalytic materials have attracted extensive attention and research in heterogeneous catalytic hydrogenation of CO2 due to their high activation efficiency for CO2 molecules. However, due to the random nature of the active interface formed between the active sites of the noble metal nanoparticles and the metal oxide support, traditional supported noble metal-based catalysts require high pressure to achieve CO2 hydrogenation reduction, and the selectivity for the high-value product methanol is low, resulting in excessive cost and energy consumption in practical applications. Furthermore, traditional noble metal active sites are prone to agglomeration and deactivation under high-temperature and high-pressure reducing atmospheres. Summary of the Invention

[0004] In order to overcome the problems of catalytic stability and product selectivity of catalysts for CO2 hydrogenation in the prior art, the purpose of the present invention is to provide a highly stable precious metal-based catalyst based on strong interaction between metal supports, a preparation method and its application in the catalytic hydrogenation of carbon dioxide to methanol.

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

[0006] A method for preparing a highly stable noble metal-based catalyst based on strong interaction between metal supports comprises the following steps:

[0007] A dispersion containing a noble metal precursor and a metal oxide support is mixed with an alkali metal salt, and then a hydrazine hydrate solution is added until the mixed solution becomes a gray-brown flocculent solution. The mixed solution is then evaporated to dryness and calcined to obtain a highly stable noble metal-based catalyst based on strong interaction with the metal support.

[0008] Furthermore, the noble metal precursor is platinum nitrate, palladium nitrate, silver nitrate or rhodium nitrate.

[0009] Furthermore, the metal oxide carrier is zinc oxide, titanium dioxide or zirconium oxide.

[0010] Furthermore, the alkali metal salt is sodium chloride, potassium chloride or lithium chloride.

[0011] Furthermore, the ratio of the noble metal precursor to the metal oxide support is 0.0001 mol:0.2-1.0 g.

[0012] Furthermore, the ratio of the noble metal precursor to deionized water is 0.0001 mol:20-40 mL.

[0013] Furthermore, the ratio of the noble metal precursor to the alkali metal salt is 0.0001 mol:0.0005-0.001 mol;

[0014] The ratio of the noble metal precursor to hydrazine hydrate is 0.0001 mol:2-5 mL, and the concentration of the hydrazine hydrate solution is 2 mol·L -1 .

[0015] Furthermore, the calcination temperature is 350-400°C, the calcination atmosphere is hydrogen, the calcination time is 2-3h, and the heating rate is 1-2.5°C·min -1 .

[0016] A highly stable noble metal-based catalyst based on strong metal-support interactions.

[0017] Application of a highly stable noble metal-based catalyst based on strong metal-support interaction in the heterogeneous catalytic hydrogenation of CO2 to methanol.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention utilizes the bridge charge transfer effect of alkali metal elements to enhance the transfer rate of charge balance between noble metal nanoparticles and metal oxide supports in supported noble metal-based catalysts, thereby accelerating the induction of metal oxide supports to migrate and overflow to the surface of noble metal nanoparticles under a high-pressure reducing atmosphere and forming a thin layer coating structure on the surface of noble metal nanoparticles. The core-shell coating structure formed is utilized to improve the stability and anti-sintering performance of noble metal active centers in a high-pressure reducing atmosphere, and inhibit the agglomeration and deactivation of nanoparticles. By adding a hydrazine hydrate reducing agent, the migration rate of the metal oxide support to the surface of the noble metal nanoparticles is regulated, and further, through the synergistic effect and rapid electron transfer effect between the oxide support and the coating structure formed by the noble metal nanoparticles, the adsorption and activation mode of CO2 molecules on the noble metal nanoparticles are adjusted. At the same time, the "lattice charge balance" driving force of the metal oxide support enables the active hydrogen (H*) dissociated from the metal active site to continuously overflow to the surface of the active center with a low energy barrier, thereby inhibiting the generation of CO and CH4 products in the heterogeneous catalytic hydrogenation process of CO2, and greatly improving the selectivity of the product methanol. The catalyst prepared by the present invention is heated at 280°C, 3 MPa and a space velocity of 12,000 h -1 Under the conditions of a gas ratio of 70% H2:25% CO2:5% N2, a CO2 conversion efficiency exceeding 6% and a product methanol selectivity exceeding 75% were achieved, with stable operation for over 100 hours. The preparation method described in this invention is universally applicable to a variety of precious metal and metal oxide supports. The synthesis method is simple and economical, and is expected to address the technical bottlenecks of poor stability and sintering of traditional precious metal-based catalysts in CO2 catalytic hydrogenation reactions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 High-angle annular dark field scanning transmission (HAADF-STEM) images of the conventional Pd / ZnO catalyst of the present invention before and after the catalytic reaction, wherein (a) is before the catalytic reaction and (b) is after the catalytic reaction;

[0021] Figure 2 This is a high-resolution transmission electron microscopy (HR-TEM) image of the highly stable Pd-Na@ZnO / ZnO catalyst of Example 1 of the invention.

[0022] Figure 3 These are high-angle annular dark field scanning transmission (HAADF-STEM) images of the highly stable Pd-Na@ZnO / ZnO catalyst before and after the reaction in Example 1 of the present invention, where (a) is before the catalytic reaction and (b) is after the catalytic reaction.

[0023] Figure 4 This is the temperature-programmed reduction spectrum (H2-TPR) of Pd / ZnO and Pd-Na@ZnO / ZnO catalysts in Example 1 of the present invention.

[0024] Figure 5 These are the activity test results of the Pd / ZnO and Pd-Na@ZnO / ZnO catalysts of Example 1 of the present invention.

[0025] Figure 6 These are the Raman spectra of the Pd / ZnO catalysts of Comparative Example 1 and Pd-Na@ZnO / ZnO catalysts of Example 1 before and after the reaction. DETAILED DESCRIPTION

[0026] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in a variety of different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0027] This invention enhances the catalytic stability and product selectivity of CO2 hydrogenation by designing a highly stable catalytic system with a fully exposed active interface. This invention will provide a scientific basis and theoretical foundation for the design of high-performance materials for CO2 hydrogenation and the selection of methods for regulating product selectivity, and has significant application prospects in the fields of CO2 emission reduction, control, and high-value conversion.

[0028] The present invention relates to a method for preparing a highly stable noble metal-based catalyst based on a strong interaction between a metal support and a catalyst. The method utilizes the bridge charge transfer effect of an alkali metal element to enhance the charge balance transfer rate between noble metal nanoparticles and a metal oxide support in a supported noble metal-based catalyst, thereby accelerating the induction of the metal oxide support to migrate and overflow to the surface of the noble metal nanoparticles under a high-pressure reducing atmosphere, and forming a thin layer coating structure on the surface of the noble metal nanoparticles. The core-shell coating structure thus formed is utilized to enhance the stability and sintering resistance of the noble metal active center in a high-pressure reducing atmosphere, and inhibit the agglomeration and deactivation of the nanoparticles. Through the synergistic effect and rapid electron transfer effect between the coating structure formed by the oxide support and the noble metal nanoparticles, the adsorption and activation mode of CO2 molecules on the noble metal nanoparticles is regulated. At the same time, the "lattice charge balance" driving force of the metal oxide support enables the active hydrogen (H*) dissociated from the metal active site to continuously overflow to the surface of the active center with a low energy barrier, thereby inhibiting the generation of CO and CH4 products in the heterogeneous catalytic hydrogenation of CO2 and significantly improving the selectivity of the product methanol.

[0029] Specifically, the preparation method of the highly stable noble metal-based catalyst based on strong interaction between metal supports of the present invention comprises the following steps:

[0030] (1) 0.0001 mol of a noble metal precursor (which may be one of platinum nitrate, palladium nitrate, silver nitrate, and rhodium nitrate) and 0.2-1.0 g of a metal oxide carrier (which may be one of zinc oxide, titanium dioxide, and zirconium oxide) are uniformly dispersed in 20-40 mL of deionized water under ultrasonic oscillation. When the mixed solution is ultrasonically oscillated, the ultrasonic power is set to 40% and the temperature is set to 15-20°C.

[0031] (2) adding 0.0005-0.001 mol of an alkali metal salt (which may be one of sodium chloride, potassium chloride and lithium chloride) to the mixed solution obtained in step (1) and mixing them uniformly under ultrasonic oscillation. When ultrasonically oscillating the mixed solution, the ultrasonic power is set to 40% and the temperature is set to 15-20°C.

[0032] (3) Add 2-5 mL of 2 mol·L -1 The mixed solution is stirred at a stirring rate of 500-800 rpm and a temperature of 40-60° C. until it becomes a gray-brown flocculent solution.

[0033] (4) The mixed solution obtained in step (3) was subjected to step-by-step pressure reduction rotary evaporation treatment, the water area temperature was set to 60-65 ° C, the rotation speed was set to 120-140 rpm, and the vacuum reduction rate was 10 mbar min -1 .

[0034] (5) Dry the solid sample obtained in step (4) at 60-80°C for 6-12 hours.

[0035] (6) Calcinate the solid sample obtained in step (5) at 350-400°C in a hydrogen atmosphere for 2-3 hours at a heating rate of 1-2.5°C·min -1 .

[0036] The highly stable noble metal-based catalyst prepared by the invention based on the strong interaction between metal supports has a core-shell active center.

[0037] The application of the highly stable noble metal-based catalyst based on the strong interaction between the metal support prepared by the present invention in the CO2 heterogeneous catalytic hydrogenation to methanol reaction is as follows: at 280 ° C, 3 MPa, and a space velocity of 12,000 h -1 Under the conditions of gas ratio of 70% H2:25% CO2:5% N2, the CO2 conversion efficiency is higher than 6%, and the selectivity of product methanol is greater than 75%. The efficiency of CO2 catalytic hydrogenation to methanol is stably maintained for more than 100 hours, with excellent catalytic efficiency and stability.

[0038] The following are specific examples.

[0039] Comparative Example 1 Preparation of Traditional Pd / ZnO Catalyst

[0040] 0.025 g of palladium nitrate and 0.5 g of zinc oxide carrier were uniformly dispersed in 30 mL of deionized water under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 15 °C. Then 4 mL of 2 mol·L -1 The mixed solution was stirred at a stirring rate of 600 rpm and a temperature of 60°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set to 65°C, the rotation speed set to 130 rpm, and the vacuum reduction rate set to 10 mbar·min -1 The obtained solid powder was dried at 80 °C for 12 h and calcined at 400 °C in a hydrogen atmosphere for 3 h at a heating rate of 2.5 °C·min -1 , and finally obtained Pd / ZnO catalyst.

[0041] See also Figure 1 In (a) and (b), Figure 1 HAADF-STEM shows that for traditional Pd / ZnO catalysts, the Pd active centers undergo obvious agglomeration before and after the CO2 catalytic hydrogenation reaction, and the particle size agglomerates from 2-3nm to 7-8nm.

[0042] Example 1 Preparation of highly stable Pd-Na@ZnO / ZnO catalyst

[0043] 0.025g of palladium nitrate and 0.5g of zinc oxide carrier were uniformly dispersed in 40mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 20℃. 0.059g of sodium chloride was added to the above solution and continued to mix under ultrasonic oscillation. Then 5mL of 2mol·L -1 The mixed solution was stirred at a stirring rate of 800 rpm and a temperature of 60°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set at 65°C, the rotation speed set at 140 rpm, and the vacuum reduction rate set at 10 mbar·min -1 The obtained solid powder was dried at 80 °C for 12 h and calcined at 400 °C in a hydrogen atmosphere for 3 h at a heating rate of 2.5 °C·min -1 , and finally obtained Pd-Na@ZnO / ZnO catalyst.

[0044] See also Figure 2 ,Depend on Figure 2From the HR-TEM image, it can be seen that a Pd@ZnO core-shell coating structure is formed on the surface of the Pd-Na@ZnO / ZnO catalyst. This structure is due to the bridge charge transfer effect of Na species, which enhances the transfer rate of charge balance between the noble metal nanoparticles and the metal oxide support in the supported noble metal-based catalyst, thereby accelerating the induction of the metal oxide support to migrate and overflow to the surface of the noble metal nanoparticles under a high-pressure reducing atmosphere and form a thin layer coating structure on the surface of the noble metal nanoparticles.

[0045] See also Figure 3 In (a) and (b), Figure 3 HAADF-STEM shows that for the highly stable Pd-Na@ZnO / ZnO catalyst, there is no obvious change in the particle size of the active site before and after the reaction. This is mainly due to the Pd@ZnO active center with its surface core-shell coating structure, which significantly improves the stability and anti-sintering performance of the precious metal active center in a high-pressure reducing atmosphere, thereby inhibiting the agglomeration and deactivation of the nanoparticles.

[0046] Example 2 Preparation of highly stable Pd-K@ZnO / ZnO catalyst

[0047] 0.025g of palladium nitrate and 0.5g of zinc oxide carrier were uniformly dispersed in 30mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 20℃. 0.059g of potassium chloride was added to the above solution and continued to mix under ultrasonic oscillation. Then 5mL of 2mol·L -1 The mixed solution was stirred at a stirring rate of 800 rpm and a temperature of 60°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set at 65°C, the rotation speed set at 140 rpm, and the vacuum reduction rate set at 10 mbar·min -1 The obtained solid powder was dried at 80 °C for 12 h and calcined at 400 °C in a hydrogen atmosphere for 3 h at a heating rate of 2.5 °C·min -1 , and finally obtained Pd-K@ZnO / ZnO catalyst.

[0048] Example 3 Preparation of highly stable Pd-Na@ZrO2 / ZrO2 catalyst

[0049] 0.025g of palladium nitrate and 0.5g of zirconium oxide carrier were uniformly dispersed in 30mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 20℃. 0.059g of sodium chloride was added to the above solution and continued to mix under ultrasonic oscillation. Then 5mL of 2mol·L -1The mixed solution was stirred at a stirring rate of 800 rpm and a temperature of 60°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set at 65°C, the rotation speed set at 140 rpm, and the vacuum reduction rate set at 10 mbar·min -1 The obtained solid powder was dried at 80 °C for 12 h and calcined at 400 °C in a hydrogen atmosphere for 3 h at a heating rate of 2.5 °C·min -1 , and finally obtained Pd-Na@ZrO2 / ZrO2 catalyst.

[0050] Example 4 Preparation of highly stable Rh-Na@ZnO / ZnO catalyst

[0051] 0.0289g of rhodium nitrate and 0.5g of zinc oxide carrier were uniformly dispersed in 30mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 20℃. 0.059g of sodium chloride was added to the above solution and continued to mix under ultrasonic oscillation. Then 5mL of 2mol·L -1 The mixed solution was stirred at a stirring rate of 800 rpm and a temperature of 60°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set at 65°C, the rotation speed set at 140 rpm, and the vacuum reduction rate set at 10 mbar·min -1 The obtained solid powder was dried at 80 °C for 12 h and calcined at 400 °C in a hydrogen atmosphere for 3 h at a heating rate of 2.5 °C·min -1 , and finally obtained Rh-Na@ZnO / ZnO catalyst.

[0052] Example 5 Catalytic CO2 Hydrogenation Activity and Stability Test

[0053] The heterogeneous catalytic hydrogenation of CO2 was carried out in a fixed-bed tubular reactor (304.8 mm in length and 9.1 mm in inner diameter). Before activity testing, the catalyst (150 mg) was pretreated with H2 at 300°C for 60 min. The gas mixture ratio (volume ratio) was H2 / CO2 / N2 = 3 / 1 / 1 (N2 was used as an internal standard), and the gas flow rate was 30 mL / min. -1 The reaction was carried out at 200-280°C and 30 bar, and the products were analyzed online by gas chromatography (Clarus 580; PerkinElmer) equipped with a TCD and flame ionization detector. The specific calculation formula for catalytic activity is as follows:

[0054]

[0055]

[0056]

[0057]

[0058] Where CO2 conversion is the carbon dioxide concentration, n CO2,in is the input carbon dioxide molar amount, n CO2,out To output the molar amount of carbon dioxide, MeOH selectivity is the methanol selectivity, n MeOH,out is the molar amount of methanol output, n CO,out is the molar amount of carbon monoxide output, MeOH specific yield is the methanol yield, F CO2 is the CO2 partial pressure, M MeOH is the output mass of methanol, m cat is the mass of the catalyst, w m is the metal loading.

[0059] The stability test of the catalytic reaction was carried out under the following conditions: the catalyst mass was 150 mg, the mixed gas ratio was H2 / CO2 / N2=3 / 1 / 1 (N2 was used as the internal standard), and the gas flow rate was 30 mL min -1 The stability test was carried out at 280 °C and 30 bar, and the products were analyzed online by gas chromatography (Clarus 580; PerkinElmer) equipped with TCD and flame ionization detector.

[0060] See also Figure 5 ,Depend on Figure 5 The activity test results show that the Pd-Na@ZnO / ZnO catalyst prepared by the present invention has a high activity at 280℃, 3Mpa and a space velocity of 12,000h -1 Under the conditions of gas ratio of 70% H2:25% CO2:5% N2, the CO2 conversion efficiency is higher than 6%, and the selectivity of product methanol is greater than 75%.

[0061] See also Figure 6 ,Depend on Figure 6 The Raman spectrum of the catalyst shows that the surface of the highly stable Pd-Na@ZnO / ZnO catalyst has characteristic peaks of the Pd@ZnO active center with a core-shell coating structure.

[0062] Example 6

[0063] 0.0001 mol of platinum nitrate and 0.5 g of titanium dioxide carrier were uniformly dispersed in 20 mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 18 ° C. 0.0005 mol of sodium chloride was added to the above solution and continued to mix under ultrasonic oscillation. Then 2 mL of 2 mol·L -1 The mixed solution was stirred at a stirring rate of 500 rpm and a temperature of 60°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set to 60°C, the rotation speed set to 120 rpm, and the vacuum reduction rate set to 10 mbar·min -1 The obtained solid powder was dried at 60 °C for 12 h and calcined at 350 °C in a hydrogen atmosphere for 3 h at a heating rate of 1 °C·min -1 , and finally a highly stable noble metal-based catalyst based on strong interactions between metal and support was obtained.

[0064] Example 7

[0065] 0.025g of silver nitrate and 0.5g of zinc oxide carrier were uniformly dispersed in 25mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 20℃. 0.001mol of sodium chloride was added to the above solution and continued to mix uniformly under ultrasonic oscillation. Then 3mL of 2mol·L -1 The mixed solution was stirred at a stirring rate of 600 rpm and a temperature of 40°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set at 65°C, the rotation speed set at 130 rpm, and the vacuum reduction rate set at 10 mbar·min -1 The obtained solid powder was dried at 80 °C for 6 h and calcined at 400 °C in a hydrogen atmosphere for 2 h at a heating rate of 2 °C min -1 , and finally a highly stable noble metal-based catalyst based on strong interactions between metal and support was obtained.

[0066] Example 8

[0067] 0.025g of palladium nitrate and 0.5g of zirconium oxide carrier were uniformly dispersed in 35mL of deionized water under ultrasonic oscillation. The ultrasonic power was set to 40% and the temperature was set to 15℃. 0.0008mol of sodium chloride was added to the above solution and continued to mix under ultrasonic oscillation. Then 4mL of 2mol·L -1The mixed solution was stirred at a stirring rate of 700 rpm and a temperature of 50°C until it turned light gray. The mixed solution was subjected to a step-by-step pressure reduction rotary evaporation process, with the water temperature set at 65°C, the rotation speed set at 140 rpm, and the vacuum reduction rate set at 10 mbar·min -1 The obtained solid powder was dried at 70 °C for 10 h and calcined at 370 °C in a hydrogen atmosphere for 2.5 h at a heating rate of 1.5 °C·min -1 , and finally a highly stable noble metal-based catalyst based on strong interactions between metal and support was obtained.

[0068] Example 9

[0069] Same as Example 1, except that the amount of sodium chloride is 5 times the mass of sodium chloride in Example 1.

[0070] Example 10

[0071] Same as Example 1, except that the amount of sodium chloride used is 15 times the mass of sodium chloride in Example 1.

[0072] See also Figure 4 In the figure, 1% Na-Pd / ZnO corresponds to Example 1, 5% Na-Pd / ZnO corresponds to Example 9, and 15% Na-Pd / ZnO corresponds to Example 10. In Examples 9 and 10, the Na content in Example 1 is increased to 5 times / 15 times, respectively. Figure 4 From the temperature-programmed reduction spectrum of the catalyst, it can be seen that on the surface of the traditional Pd / ZnO catalyst, an obvious inverted peak of PdH appears, which is formed by the adsorption of H2 on the surface of Pd nanoparticles. In contrast, for the Pd@ZnO active center of the core-shell coating structure on the surface of the highly stable Pd-Na@ZnO / ZnO catalyst, an obvious reduction peak of PdZnO species is presented.

[0073] The catalyst prepared by the present invention is heated at 280°C, 3 MPa and a space velocity of 12,000 h -1 Under the conditions of a gas ratio of 70% H2:25% CO2:5% N2, a CO2 conversion efficiency exceeding 6% and a selectivity for the product methanol exceeding 75% were achieved, with stable operation for over 100 hours. The preparation method disclosed in this invention is universally applicable to a variety of precious metal and metal oxide supports. The synthesis method is simple and economical, and is expected to address the technical bottlenecks of poor stability and sintering of traditional precious metal-based catalysts in CO2 catalytic hydrogenation reactions, promoting theoretical innovation and technological progress in the fields of CO2 resource utilization and renewable energy development.

[0074] The above description is merely a description of the preferred embodiment of the present invention and is not to be construed as limiting the claims. The present invention is not limited to the above embodiment, and variations in the specific structure are permitted. Any variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for preparing a highly stable noble metal-based catalyst based on strong interaction between metal supports, characterized in that: The following steps are involved: A dispersion containing a noble metal precursor and a metal oxide support is mixed with an alkali metal salt, and then a hydrazine hydrate solution is added until the mixed solution becomes a gray-brown flocculent solution. The mixed solution is then evaporated to dryness and calcined to obtain a highly stable noble metal-based catalyst based on a strong interaction between the metal support and the catalyst. The noble metal precursor is platinum nitrate, palladium nitrate, silver nitrate or rhodium nitrate; The metal oxide support is zinc oxide, titanium dioxide or zirconium oxide; The alkali metal salt is sodium chloride, potassium chloride or lithium chloride.

2. The method for preparing a highly stable noble metal-based catalyst based on strong interaction between metal supports according to claim 1, characterized in that: The ratio of the noble metal precursor to the metal oxide support is 0.0001 mol:0.2-1.0 g.

3. The method for preparing a highly stable noble metal-based catalyst based on strong interaction between metal supports according to claim 1, characterized in that: The ratio of noble metal precursor to deionized water is 0.0001 mol:20-40 mL.

4. The method for preparing a highly stable noble metal-based catalyst based on strong interaction between metal supports according to claim 1, characterized in that: The ratio of noble metal precursor to alkali metal salt is 0.0001mol:0.0005-0.001mol; The ratio of the noble metal precursor to the hydrazine hydrate solution is 0.0001 mol:2-5 mL, and the concentration of the hydrazine hydrate solution is 2 mol·L -1 .

5. The method for preparing a highly stable noble metal-based catalyst based on strong interaction between metal supports according to claim 1, characterized in that: The calcination temperature is 350-400℃, the calcination atmosphere is hydrogen, the calcination time is 2-3h, and the heating rate is 1-2.5℃·min -1 .

6. A highly stable noble metal-based catalyst based on strong interaction between metal and support, prepared according to the method of any one of claims 1 to 5.

7. Use of a highly stable noble metal-based catalyst based on strong metal-support interaction prepared by the method according to any one of claims 1 to 5 in the CO2 heterogeneous catalytic hydrogenation reaction to produce methanol.

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