Platinum group metal supported catalyst, its preparation method and application in carbon dioxide hydrogenation

Abstract

The application provides a platinum group metal supported catalyst, a preparation method thereof and application of the catalyst in carbon dioxide hydrogenation. The preparation method comprises the following steps: mixing a salt of a platinum group metal active component, alkali and ethylene glycol to obtain platinum group metal particle colloid; and mixing the obtained platinum group metal particle colloid with a chromium carrier and a promoter to obtain the platinum group metal supported catalyst. The catalyst prepared by the preparation method has the following advantages: the particle size of the active component of the catalyst is easy to control, the dispersion is good, the structure is stable, no impurity phase is introduced, and the alcohol product is specifically generated in the catalytic carbon dioxide hydrogenation reaction, the selectivity of the alcohol product reaches more than 90%, and the preparation method is easy to repeat.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and relates to a supported catalyst, particularly a platinum group metal supported catalyst and its preparation method and its application in carbon dioxide hydrogenation. Background Technology

[0002] As human demand for energy continues to rise, the greenhouse effect and ocean acidification caused by massive CO2 emissions are impacting the sustainable development of human society. CO2 is a cheap and non-toxic carbon resource. Converting CO2 into high-value-added products (fuels or chemical feedstocks) through catalytic hydrogenation can effectively reduce CO2 emissions and thus alleviate the environmental problems caused by CO2. Meanwhile, the development of technologies such as solar power generation and electrolytic hydrogen production has made large-scale hydrogen production possible in an environmentally friendly manner, and the catalytic hydrogenation of CO2 into high-value-added products shows broad development prospects.

[0003] CO2 molecules are chemically stable and difficult to activate. CO2 has a high ionization energy, making it difficult for it to lose electrons to form CO2. + It has low-energy empty orbitals and high electron affinity, making it easy to form CO2. - If the catalyst can donate electrons when in contact with carbon dioxide, CO2 can be formed. - This facilitates activation. Platinum group elements are commonly used in the catalytic hydrogenation of carbon dioxide. However, the activation ability of a single platinum group element for carbon dioxide is often limited. Studies have shown that supports can also participate in the reaction by providing additional active centers or modifying the main active component.

[0004] CN115228468A discloses a metal composite oxide catalyst, its preparation method, and its application in the hydrogenation of carbon dioxide to ethanol. This metal composite oxide catalyst uses platinum group metals as the active metal element and gallium oxide, indium oxide, zirconium oxide, or cerium oxide as the oxide support. The preparation process involves pre-treating the oxide support with calcination followed by reduction heat treatment. This method requires high-temperature calcination and has demanding preparation conditions.

[0005] In trivalent chromium-containing inorganic compounds, chromium has a +3 valence, an intermediate state that facilitates the gain or loss of electrons, thus aiding in the activation of carbon dioxide. Chromium trioxide, a representative example of trivalent chromium-containing inorganic compounds, is a structurally stable inorganic compound commonly used in catalytic reactions. As a catalyst support, it exhibits good stability and a moderate adsorption capacity for carbon dioxide. Grisel Corro et al. used an impregnation method to support Pt on a Cr2O3 support, and the catalyst could effectively oxidize methane at low temperatures (J. Phys. Chem. C, 2019, 123, 5, 2882); Chen, Xi et al. synthesized a three-dimensional permeable Pt-supported mesoporous Cr2O3 catalyst (Pt@M-Cr2O3) by pyrolyzing MIL-101(Cr) (a Cr-containing MOF material) containing pre-impregnated Pt particles, which can achieve the catalytic degradation of toluene (Chemical Engineering Journal, 2018, 334, 768-779). The above catalyst preparation methods often require high-temperature reduction when loading metal salts, which can easily lead to the aggregation and enlargement of active component particles, thereby reducing catalytic performance and making it difficult to control the catalyst structure. Summary of the Invention

[0006] The purpose of this invention is to provide a platinum group metal supported catalyst, its preparation method, and its application in carbon dioxide hydrogenation. The catalyst has a stable structure and controllable active component particles, and can be used to catalyze carbon dioxide hydrogenation with high selectivity for alcohol products.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0009] (1) The salt, alkali and ethylene glycol of the active components of platinum group metals are mixed and reacted to obtain platinum group metal particle colloids;

[0010] (2) The platinum group metal particle colloid obtained in step (1) is mixed with a chromium support and a promoter to obtain the platinum group metal supported catalyst.

[0011] The preparation method provided by this invention first uses alkali and ethylene glycol to reduce and prepare colloidal nanoparticles of the active component, and then loads the colloidal nanoparticles of the active component onto a chromium support using a promoter. This method can prepare a uniform, stable, and easily stored colloidal solution. The size of the active component particles is easily controlled, and the dispersion is good, facilitating industrial-scale production. Chromium-containing inorganic materials are selected as the support, as they have good stability and, when used to catalyze carbon dioxide reactions, carbon dioxide is chemically adsorbed on the surface of the chromium inorganic material, facilitating adsorption and catalysis. The promoter transfers the colloidal particles from the liquid phase to the support surface, ensuring stable adsorption of platinum group element colloidal particles and preventing them from easily detaching. This method avoids the disadvantages of existing technologies that use traditional impregnation methods, which introduce other salt impurities and require high-temperature treatment, thus preventing the introduction of impurity phases and the aggregation of active metals into the support. The preparation method also exhibits good repeatability.

[0012] Preferably, the platinum group metal active component in step (1) includes any one or at least two combinations of platinum, osmium, iridium, rhodium or ruthenium. Typical but non-limiting combinations include platinum and osmium, osmium and iridium, iridium and rhodium, rhodium and ruthenium, platinum, osmium and iridium, or iridium, rhodium and ruthenium.

[0013] Preferably, the mixing process in step (1) includes: dispersing the salt of the platinum group metal active component in ethylene glycol, and then adding an ethylene glycol solution of alkali to adjust the pH to 7-13.

[0014] The pH is adjusted to 7-13, for example, 7, 8, 9, 10, 11, 12 or 13, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the reaction temperature in step (1) is 110-190℃, for example, it can be 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃ or 190℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Preferably, the reaction time in step (1) is 0.3-24h, for example, it can be 0.3h, 1h, 5h, 10h, 15h, 20h or 24h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the reaction in step (1) is carried out in an inert gas atmosphere.

[0018] Preferably, the mixing process in step (2) includes: dispersing the chromium support in an organic solvent, and then mixing and stirring it sequentially with platinum group metal particle colloids and an accelerator.

[0019] Preferably, the organic solvent includes any one or a combination of at least two of acetone, methanol, ethanol, ethylene glycol, propylene glycol, acetonitrile, ethyl acetate, or glycerol. Typical but non-limiting combinations include combinations of acetone and methanol, methanol and ethylene glycol, acetonitrile and ethyl acetate, acetone and acetonitrile, or combinations of acetone, ethanol, propylene glycol, acetonitrile, and ethyl acetate.

[0020] Preferably, the mixture in step (2) is washed and dried sequentially.

[0021] Preferably, the washing method includes washing with water and organic solvents alternately.

[0022] Preferably, the drying method includes freeze drying and / or low-temperature vacuum drying.

[0023] Preferably, the chromium carrier in step (2) is a chromium-containing inorganic material.

[0024] Preferably, the chromium-containing inorganic material includes any one or a combination of at least two of chromium trioxide, chromium hydroxide (III), chromium carbonate (III), or chromium phosphate (III). Typical but non-limiting combinations include combinations of chromium trioxide and chromium hydroxide (III), combinations of chromium carbonate (III) and chromium phosphate (III), combinations of chromium trioxide, chromium hydroxide (III), and chromium carbonate (III), combinations of chromium hydroxide (III), chromium carbonate (III), and chromium phosphate (III), or combinations of chromium trioxide, chromium hydroxide (III), chromium carbonate (III), and chromium phosphate (III).

[0025] Preferably, the accelerator in step (2) includes any one or a combination of at least two of water, ammonia, trimethylamine aqueous solution, diethylamine aqueous solution, or triethylamine aqueous solution. Typical but non-limiting combinations include a combination of ammonia and trimethylamine aqueous solution, a combination of diethylamine aqueous solution and triethylamine aqueous solution, a combination of ammonia, trimethylamine aqueous solution and diethylamine aqueous solution, or a combination of ammonia, trimethylamine aqueous solution, diethylamine aqueous solution and triethylamine aqueous solution.

[0026] In a second aspect, the present invention provides a platinum group metal supported catalyst, wherein the platinum group metal supported catalyst is prepared by the preparation method described in the first aspect.

[0027] The platinum group metal supported catalyst provided by this invention uses chromium-containing inorganic materials as a support and platinum group metal nanoparticles as the active component. It has a stable structure and no impurity phase is introduced. It is specifically designed for the catalytic hydrogenation reaction of carbon dioxide to generate alcohol products with a selectivity of over 90%.

[0028] Preferably, in the platinum group metal supported catalyst, the content of the platinum group metal active component is 0.1-30 wt%, for example, it can be 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Thirdly, the present invention provides an application of the platinum group metal supported catalyst described in the second aspect, wherein the platinum group metal supported catalyst is used to catalyze the hydrogenation reaction of carbon dioxide.

[0030] Preferably, the catalytic carbon dioxide hydrogenation reaction process includes: adding the platinum group metal supported catalyst and solvent to the reaction apparatus, and introducing carbon dioxide and hydrogen to react and obtain the product.

[0031] Preferably, the molar ratio of the platinum group metal active component to carbon dioxide in the platinum group metal supported catalyst is 1:(1-5000), for example, it can be 1:1, 1:50, 1:100, 1:500, 1:1000, 1:1500, 1:2000, 1:2200, 1:2400, 1:2500, 1:2600, 1:2800, 1:3000, 1:3500, 1:4000, 1:4500 or 1:5000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1:(2000-3000).

[0032] Preferably, the pressure of carbon dioxide in the reaction device is 0.005-15 MPa, for example, it can be 0.005 MPa, 0.01 MPa, 0.05 MPa, 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 10 MPa or 15 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1-5 MPa.

[0033] Preferably, the pressure of hydrogen in the reaction device is 0.005-15 MPa, for example, it can be 0.005 MPa, 0.01 MPa, 0.05 MPa, 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 10 MPa or 15 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1-5 MPa.

[0034] Preferably, the solvent comprises any one or a combination of at least two of N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, dimethyl sulfoxide, or N,N-dimethylformamide. Typical but non-limiting combinations include combinations of N-methylpyrrolidone and 1,3-dimethyl-2-imidazolinone, dimethyl sulfoxide and N,N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone and dimethyl sulfoxide, 1,3-dimethyl-2-imidazolinone, dimethyl sulfoxide and N,N-dimethylformamide, or N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, dimethyl sulfoxide and N,N-dimethylformamide.

[0035] Preferably, the reaction temperature is 20-220℃, for example, it can be 20℃, 50℃, 60℃, 80℃, 100℃, 120℃, 140℃, 150℃, 160℃, 180℃, 200℃ or 220℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 60-180℃.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The catalyst active component prepared by the method provided by this invention has easily controllable particle size, good dispersibility, stable structure, and no impurity phase introduction. It specifically generates alcohol products for the catalytic hydrogenation reaction of carbon dioxide, with a selectivity of over 90% for alcohol products. The preparation method is easy to repeat. Attached Figure Description

[0038] Figure 1 This is a transmission electron microscope image of the Cr2O3 support provided in Example 1;

[0039] Figure 2 This is a transmission electron microscope (TEM) image of the platinum group metal supported catalyst provided in Example 1;

[0040] Figure 3 This is a temperature-programmed desorption curve of CO2 for the support and platinum group metal supported catalyst provided in Example 1.

[0041] Figure 4 This is a temperature-programmed desorption curve of H2 for the support and platinum group metal supported catalyst provided in Example 1.

[0042] Figure 5 These are X-ray diffraction patterns of the platinum group metal supported catalysts provided in Examples 1 and 6. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] Example 1

[0045] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0046] (1) Dissolve 0.07g H2PtCl6·6H2O in 50mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30min. Heat to 160℃ under an inert atmosphere and continue heating for 3h. After naturally cooling to room temperature, a brownish-brown, homogeneous and stable Pt colloid is obtained.

[0047] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 300 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0048] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is nano-chromium trioxide, wherein the loading of Pt is 0.5 wt%, and the size of the Pt particles is 3-5 nm.

[0049] The preparation method of nano-chromium trioxide is as follows:

[0050] Weigh 5.32g of CrCl3·6H2O and dissolve it in 200mL of deionized water. Stir until completely dissolved. Dissolve 4g of polyvinylpyrrolidone (PVP, K29-32) in 200mL of water and stir until completely dissolved. Place the PVP solution in a dropping funnel and add it dropwise to the CrCl3 solution. Adjust the dropping rate and control the addition to complete the addition within 10 minutes. After the addition is complete, continue stirring and mix for 30 minutes. Add ammonia water to the mixture to adjust the pH to 8. Keep the solution at 60℃ and age for 2 hours. Centrifuge to separate the precipitate. Wash the precipitate three times with water and anhydrous ethanol respectively. Place the precipitate in an oven and bake at 90℃ for 12 hours. After obtaining the dry powder, grind it in a mortar and pestle and calcine it at 600℃ for three hours to obtain nano-chromium trioxide.

[0051] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0052] 0.5850 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. After repeated venting five times to remove air, the carbon dioxide pressure inside the high-pressure reactor was maintained at 1.25 MPa. The molar ratio of the platinum group metal active component in the platinum group metal supported catalyst to carbon dioxide was 1:1500. Then, hydrogen was introduced to maintain the gas pressure inside the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time at 6 h, and the stirring speed at 500 rpm.

[0053] Example 2

[0054] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0055] (1) Dissolve 0.48g H2PtCl6·6H2O in 250mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30min. Heat to 160℃ under an inert atmosphere and continue heating for 3h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Pt colloid is obtained.

[0056] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0057] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is nano-chromium trioxide, wherein the loading of Pt is 3wt%, and the size of the Pt particles is 3-5nm.

[0058] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0059] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0060] 0.0975 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0061] Example 3

[0062] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0063] (1) Dissolve 0.13g RuCl3·3H2O in 250mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30min. Heat to 160℃ under an inert atmosphere and continue heating for 3h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Ru colloid is obtained.

[0064] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Ru colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0065] In this embodiment, the active component of the platinum group metal supported catalyst is Ru, and the support is nano-chromium trioxide, wherein the loading of Ru is 1 wt%, and the size of Ru particles is 3-5 nm.

[0066] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0067] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0068] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0069] Example 4

[0070] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0071] (1) Dissolve 0.10g IrCl3·3H2O in 250mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30min. Heat to 160℃ under an inert atmosphere and continue heating for 3h. After naturally cooling to room temperature, a brownish-brown, homogeneous and stable Ir colloid is obtained.

[0072] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Ir colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0073] In this embodiment, the active component of the platinum group metal supported catalyst is Ir, and the support is nano-chromium trioxide, wherein the loading of Ir is 1wt%, and the size of the Pt particles is 3-5nm.

[0074] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0075] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0076] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0077] Example 5

[0078] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0079] (1) Dissolve 0.13g K2OsCl6 in 250mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30min. Heat to 160℃ under an inert atmosphere and continue heating for 3h. After naturally cooling to room temperature, a brownish-brown, homogeneous and stable Os colloid is obtained.

[0080] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the Os colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0081] In this embodiment, the active component of the platinum group metal supported catalyst is Os, and the support is nano-chromium trioxide, wherein the loading of Os is 1 wt%, and the size of the Os particles is 3-5 nm.

[0082] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0083] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0084] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time at 6 h, and the stirring speed at 500 rpm.

[0085] Example 6

[0086] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0087] (1) Dissolve 0.14 g H2PtCl6·6H2O in 250 mL of ethylene glycol and stir at room temperature for 20 min until completely dissolved. Add ethylene glycol solution of NaOH (0.25 mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30 min. Heat to 160 °C under an inert atmosphere and continue heating for 3 h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Pt colloid is obtained.

[0088] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0089] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is nano-chromium trioxide, wherein the loading of Pt is 1 wt%, and the size of the Pt particles is 3-5 nm.

[0090] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0091] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0092] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0093] Example 7

[0094] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0095] (1) First, dissolve 0.14 g H2PtCl6·6H2O in 50 mL of ethylene glycol and stir for 10 min at room temperature until completely dissolved. Prepare an ethylene glycol solution of NaOH (0.25 mol / L) and add 50 mL dropwise to adjust the pH of the solution to 11. Continue stirring at room temperature for 30 min. Under the protection of argon atmosphere, raise the temperature to 160℃ and keep heating for 3 h. Then, cool naturally to room temperature to obtain a brownish-brown, homogeneous, and stable Pt colloid.

[0096] Then, 0.13 g RuCl3·3H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 10 min until completely dissolved. A 0.25 mol / L solution of NaOH in ethylene glycol was prepared and added dropwise in 50 mL. The pH of the solution was adjusted to 11. The mixture was stirred at room temperature for 30 min. Under an argon atmosphere, the temperature was raised to 160 °C and kept heated for 3 h. After cooling naturally to room temperature, a brownish-red, homogeneous, and stable Ru colloid was obtained.

[0097] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid and Ru colloid were slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0098] In this embodiment, the active components of the platinum group metal supported catalyst are Pt and Ru, and the support is nano-chromium trioxide, wherein the loading of Pt and Ru is 1wt% and 1wt%, respectively, and the size of Pt and Ru particles is 3-5nm.

[0099] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0100] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0101] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0102] Example 8

[0103] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0104] (1) Dissolve 0.14 g H2PtCl6·6H2O in 250 mL of ethylene glycol and stir at room temperature for 20 min until completely dissolved. Add ethylene glycol solution of NaOH (0.25 mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30 min. Heat to 160 °C under an inert atmosphere and continue heating for 3 h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Pt colloid is obtained.

[0105] (2) 5.0 g of chromium hydroxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0106] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is chromium hydroxide, wherein the loading of Pt is 1 wt%, and the size of the Pt particles is 3-5 nm.

[0107] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0108] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0109] Example 9

[0110] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0111] (1) Dissolve 0.14 g H2PtCl6·6H2O in 250 mL of ethylene glycol and stir at room temperature for 20 min until completely dissolved. Add ethylene glycol solution of NaOH (0.25 mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30 min. Heat to 160 °C under an inert atmosphere and continue heating for 3 h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Pt colloid is obtained.

[0112] (2) 5.0 g of chromium hydroxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0113] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is chromium carbonate, wherein the loading of Pt is 1 wt%, and the size of the Pt particles is 3-5 nm.

[0114] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0115] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0116] Example 10

[0117] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0118] (1) Dissolve 0.14 g H2PtCl6·6H2O in 250 mL of ethylene glycol and stir at room temperature for 20 min until completely dissolved. Add ethylene glycol solution of NaOH (0.25 mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30 min. Heat to 160 °C under an inert atmosphere and continue heating for 3 h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Pt colloid is obtained.

[0119] (2) 5.0 g of chromium phosphate was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 500 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0120] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is chromium phosphate, wherein the loading of Pt is 1 wt%, and the size of the Pt particles is 3-5 nm.

[0121] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0122] 0.2925 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1.25 MPa and slowly released. The gas was exchanged 5 times to remove air. The carbon dioxide pressure in the high-pressure reactor was maintained at 1.25 MPa. Then, hydrogen was introduced to maintain the gas pressure in the high-pressure reactor at 5.00 MPa. The reaction temperature was set at 120 °C, the reaction time was 6 h, and the stirring speed was 500 rpm.

[0123] Example 11

[0124] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0125] (1) Dissolve 0.02g H2PtCl6·6H2O in 50mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 7. Continue stirring at room temperature for 30min. Heat to 110℃ under an inert atmosphere and continue heating for 24h. After naturally cooling to room temperature, a brownish-brown, homogeneous and stable Pt colloid is obtained.

[0126] (2) 5.00 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 300 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0127] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is nano-chromium trioxide, wherein the loading of Pt is 0.1 wt%, and the size of the Pt particles is 3-5 nm.

[0128] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0129] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0130] 2.1938 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 1 MPa and slowly released. The mixture was vented repeatedly 5 times to remove air. The carbon dioxide pressure inside the high-pressure reactor was maintained at 1 MPa. The molar ratio of the platinum group metal active component in the platinum group metal supported catalyst to carbon dioxide was 1:2000. Hydrogen was then introduced to maintain the gas pressure inside the high-pressure reactor at 1 MPa. The reaction temperature was set at 60 °C, the reaction time at 6 h, and the stirring speed at 500 rpm.

[0131] Example 12

[0132] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0133] (1) Dissolve 4.2000g H2PtCl6·6H2O in 50mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 13. Continue stirring at room temperature for 30min. Heat to 190℃ under an inert atmosphere and continue heating for 0.3h. After naturally cooling to room temperature, a brownish-brown, homogeneous, and stable Pt colloid is obtained.

[0134] (2) 5.00 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 300 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0135] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is nano-chromium trioxide, wherein the loading of Pt is 20wt%, and the size of the Pt particles is 3-5nm.

[0136] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0137] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0138] 0.0073 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 5 MPa and slowly released. The mixture was vented repeatedly 5 times to remove air. The carbon dioxide pressure inside the high-pressure reactor was maintained at 5 MPa. The molar ratio of the platinum group metal active component in the platinum group metal supported catalyst to carbon dioxide was 1:3000. Hydrogen was then introduced to maintain the gas pressure inside the high-pressure reactor at 5 MPa. The reaction temperature was set at 180 °C, the reaction time at 6 h, and the stirring speed at 500 rpm.

[0139] Example 13

[0140] This embodiment provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0141] (1) Dissolve 0.07g H2PtCl6·6H2O in 50mL ethylene glycol and stir at room temperature for 20min until completely dissolved. Add ethylene glycol solution of NaOH (0.25mol / L) to adjust the pH of the solution to 11. Continue stirring at room temperature for 30min. Heat to 160℃ under an inert atmosphere and continue heating for 3h. After naturally cooling to room temperature, a brownish-brown, homogeneous and stable Pt colloid is obtained.

[0142] (2) 5.0 g of nano-chromium trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, the prepared Pt colloid was slowly added dropwise using a constant pressure funnel. After stirring for 2 h, 300 mL of deionized water was added and stirring was continued for 3 h. After washing with water, the catalyst was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0143] In this embodiment, the active component of the platinum group metal supported catalyst is Pt, and the support is nano-chromium trioxide, wherein the loading of Pt is 0.5 wt%, and the size of the Pt particles is 3-5 nm.

[0144] The preparation method of nano-chromium trioxide is the same as that in Example 1.

[0145] This embodiment also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process of which is as follows:

[0146] 0.1755 g of the platinum group metal supported catalyst was dispersed in 50 mL of N-methylpyrrolidone and placed in a high-pressure reactor. Carbon dioxide was introduced at 15 MPa and slowly released. The mixture was vented repeatedly 5 times to remove air. The carbon dioxide pressure inside the high-pressure reactor was maintained at 15 MPa. The molar ratio of the platinum group metal active component in the platinum group metal supported catalyst to carbon dioxide was 1:5000. Hydrogen was then introduced to maintain the gas pressure inside the high-pressure reactor at 15 MPa. The reaction temperature was set at 220 °C, the reaction time at 6 h, and the stirring speed at 500 rpm.

[0147] Example 14

[0148] This embodiment provides a method for preparing a platinum group metal supported catalyst. Compared with Example 1, the reaction temperature of step (1) is controlled at 100°C, and the rest are the same as in Example 1.

[0149] Example 15

[0150] This embodiment provides a method for preparing a platinum group metal supported catalyst. Compared with Example 1, the reaction temperature of step (1) is controlled at 200°C, and the rest are the same as in Example 1.

[0151] Comparative Example 1

[0152] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0153] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0154] (2) 2.0 g of alumina was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0155] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is alumina, wherein the loading amount of Pt is 1 wt%.

[0156] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0157] Comparative Example 2

[0158] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0159] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0160] (2) 2.0 g of activated carbon was evenly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0161] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is activated carbon, wherein the loading amount of Pt is 1 wt%.

[0162] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0163] Comparative Example 3

[0164] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0165] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0166] (2) 2.0 g of silica was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0167] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is silicon dioxide, wherein the loading amount of Pt is 1 wt%.

[0168] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0169] Comparative Example 4

[0170] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0171] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0172] (2) 2.0 g of zinc oxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0173] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is zinc oxide, wherein the loading amount of Pt is 1 wt%.

[0174] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0175] Comparative Example 5

[0176] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0177] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0178] (2) 2.0 g of titanium dioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0179] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is titanium dioxide, wherein the loading amount of Pt is 1 wt%.

[0180] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0181] Comparative Example 6

[0182] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0183] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0184] (2) 2.0 g of tungsten trioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0185] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is tungsten trioxide, wherein the loading amount of Pt is 1 wt%.

[0186] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0187] Comparative Example 7

[0188] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0189] (1) Dissolve 1g H2PtCl6·6H2O in 50 mL of ethylene glycol, stir at room temperature for 10 min until completely dissolved, add 50 mL of ethylene glycol solution of NaOH (0.25 mol / L), continue stirring at room temperature for 30 min, heat to 160℃ under inert atmosphere protection, continue heating for 3 h, and then cool naturally to room temperature to obtain brownish-brown homogeneous and stable Pt colloid;

[0190] (2) 2.0 g of manganese dioxide was uniformly dispersed in 100 mL of ethylene glycol. Under an inert atmosphere, 18.75 g of Pt colloid was slowly added dropwise using a constant pressure funnel. The mixture was stirred for 2 h, then 300 mL of deionized water was added. The mixture was stirred for another 3 h. After washing with water, the mixture was freeze-dried under vacuum for 10 h to obtain the platinum group metal supported catalyst.

[0191] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is manganese dioxide, wherein the loading amount of Pt is 1 wt%.

[0192] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0193] Comparative Example 8

[0194] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method of which adopts the literature "Total Oxidation of Methane over Pt / Cr2O3 Catalyst at Low Temperature: Effect of Pt 0 –Pt x+ Prepared by impregnation method in "Dipoles at the Metal–Support Interface" (J.Phys.Chem.C,2019,123,5,2882–2893).

[0195] The preparation method includes the following steps:

[0196] 5.0 g of chromium trioxide powder was impregnated in 200 mL of an aqueous solution containing platinum hexachloride with a concentration of 0.07 g / mL. After the suspension was magnetically stirred at room temperature for 1 hour, the catalyst was recovered by filtration and thoroughly washed to remove chlorine and other unreacted substances. The catalyst was dried at 120 °C overnight and calcined at 600 °C for 4 hours in a tube furnace under a nitrogen atmosphere. After cooling to room temperature, the platinum group metal supported catalyst was obtained.

[0197] In this comparative example, the active component of the platinum group metal supported catalyst is Pt, and the support is chromium trioxide, wherein the loading of Pt is 1 wt%.

[0198] This comparative example also provides a platinum group metal supported catalyst for catalyzing the hydrogenation reaction of carbon dioxide, the reaction process being the same as in Example 3.

[0199] Comparative Example 9

[0200] This comparative example provides a method for preparing a platinum group metal supported catalyst, the method comprising the following steps:

[0201] 0.07 g H2PtCl6·6H2O and 5.0 g nano-chromium trioxide were dispersed in water and ethylene glycol respectively to obtain mixed solutions. The pH of the mixed solutions was adjusted to 11 using sodium hydroxide solution. The two mixed solutions were then mixed and reacted at 160 °C for 3 h to obtain the preparation method of the platinum group metal supported catalyst.

[0202] The products of the hydrogenation reaction of carbon dioxide catalyzed by the platinum group metal supported catalysts provided in the examples and comparative examples were analyzed by gas chromatography, and the results are listed in Table 1.

[0203] Figure 1 and Figure 2 The images show transmission electron microscopy (TEM) images of the Cr2O3 support and the platinum group metal supported catalyst provided in Example 1, respectively. As can be seen from the images, the particle size of the chromium trioxide support is about 50 nm to 100 nm, and the particle size of the platinum metal particles supported on the chromium trioxide support is about 3 to 5 nm. Figure 3 and Figure 4 The CO2 temperature-programmed desorption curves and H2 temperature-programmed desorption curves of the support and the platinum group metal supported catalyst provided in Example 1 are shown respectively. It can be seen that the nano-chromium trioxide prepared in the example has a certain adsorption effect on carbon dioxide. After loading platinum, the carbon dioxide adsorption peak position shifted to a certain extent, proving that a certain synergistic effect occurred between the support and the metal. Figure 5 The X-ray diffraction patterns of the platinum group metal supported catalysts provided in Examples 1 and 6 show that the prepared nano-chromium trioxide support is consistent with the standard and has good crystallinity. No platinum diffraction peaks were observed after platinum loading, which may be due to the good dispersion of the metal on the support.

[0204] Table 1

[0205]

[0206]

[0207] In the table, " / " indicates no data.

[0208] As can be seen from Table 1, the platinum group metal supported catalyst prepared by the preparation method provided by the present invention can effectively catalyze the hydrogenation of carbon dioxide into alcohol products, with a selectivity of over 90% for alcohol products.

[0209] In summary, the catalyst active component prepared by the method provided by this invention has easily controllable particle size, good dispersibility, stable structure, and no impurity phase introduction. It specifically generates alcohol products for the catalytic hydrogenation reaction of carbon dioxide, with a selectivity of over 90% for alcohol products. The preparation method is also easy to repeat.

[0210] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a platinum group metal supported catalyst for the catalytic hydrogenation of carbon dioxide to alcohol products, characterized in that, The preparation method includes the following steps: (1) The salt, alkali and ethylene glycol of the active components of platinum group metals are mixed and reacted to obtain platinum group metal particle colloids; (2) The platinum group metal particle colloid obtained in step (1) is mixed with a chromium support and a promoter to obtain the platinum group metal supported catalyst; the chromium support includes any one or a combination of at least two of chromium trioxide, chromium hydroxide, chromium carbonate or chromium phosphate, and the chromium in the chromium support is trivalent.

2. The preparation method according to claim 1, characterized in that, The platinum group metal active component in step (1) includes any one or a combination of at least two of platinum, osmium, iridium, rhodium or ruthenium.

3. The preparation method according to claim 1, characterized in that, The mixing process in step (1) includes: dispersing the salt of the platinum group metal active component in ethylene glycol, and then adding an ethylene glycol solution of alkali to adjust the pH to 7-13.

4. The preparation method according to claim 1, characterized in that, The reaction temperature in step (1) is 110-190℃.

5. The preparation method according to claim 1, characterized in that, The reaction time in step (1) is 0.3-24 hours.

6. The preparation method according to claim 1, characterized in that, The reaction described in step (1) is carried out in an inert gas atmosphere.

7. The preparation method according to claim 1, characterized in that, The mixing process in step (2) includes: dispersing the chromium support in an organic solvent, and then mixing and stirring it sequentially with platinum group metal particle colloids and an accelerator.

8. The preparation method according to claim 7, characterized in that, The organic solvent includes any one or a combination of at least two of acetone, methanol, ethanol, ethylene glycol, propylene glycol, acetonitrile, ethyl acetate, or glycerol.

9. The preparation method according to claim 1, characterized in that, After mixing in step (2), the mixture is washed and dried sequentially.

10. The preparation method according to claim 9, characterized in that, The washing method includes washing with water and organic solvents alternately.

11. The preparation method according to claim 9, characterized in that, The drying methods include freeze drying and / or low-temperature vacuum drying.

12. The preparation method according to claim 1, characterized in that, The accelerator in step (2) includes any one or a combination of at least two of the following: water, ammonia, trimethylamine aqueous solution, diethylamine aqueous solution, or triethylamine aqueous solution.

13. A platinum group metal supported catalyst for catalytic hydrogenation of carbon dioxide to alcohol products, characterized in that, The platinum group metal supported catalyst for catalyzing the hydrogenation of carbon dioxide into alcohol products is prepared by the preparation method according to any one of claims 1-12.

14. The platinum group metal supported catalyst for the catalytic hydrogenation of carbon dioxide to alcohols according to claim 13, characterized in that, The platinum group metal supported catalyst contains 0.1-30 wt% platinum group metal active components.

15. The application of a platinum group metal supported catalyst as described in claim 13 or 14 for catalytic hydrogenation of carbon dioxide to alcohol products, characterized in that, The platinum group metal supported catalyst is used to catalyze the hydrogenation of carbon dioxide into alcohol products.

16. The application according to claim 15, characterized in that, The catalytic carbon dioxide hydrogenation process includes: adding the platinum group metal supported catalyst and solvent to the reaction apparatus, and introducing carbon dioxide and hydrogen to react and obtain the product.

17. The application according to claim 16, characterized in that, The molar ratio of the platinum group metal active component to carbon dioxide in the platinum group metal supported catalyst is 1:(1-5000).

18. The application according to claim 17, characterized in that, The molar ratio of the platinum group metal active component to carbon dioxide in the platinum group metal supported catalyst is 1:(2000-3000).

19. The application according to claim 16, characterized in that, The pressure of carbon dioxide in the reaction apparatus is 0.005-15 MPa.

20. The application according to claim 19, characterized in that, The pressure of carbon dioxide in the reaction apparatus is 1-5 MPa.

21. The application according to claim 16, characterized in that, The pressure of hydrogen in the reaction device is 0.005-15 MPa.

22. The application according to claim 21, characterized in that, The pressure of hydrogen in the reaction device is 1-5 MPa.

23. The application according to claim 16, characterized in that, The solvent includes any one or a combination of at least two of N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, dimethyl sulfoxide, or N,N-dimethylformamide.

24. The application according to claim 16, characterized in that, The reaction temperature is 20-220℃.

25. The application according to claim 24, characterized in that, The reaction temperature is 60-180℃.

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