Indium oxide-based supported catalyst, and preparation method and application thereof

Abstract

The present application relates to a kind of indium oxide-based supported catalyst and its preparation method and application, the indium oxide-based supported catalyst includes indium oxide carrier and active component supported on indium oxide carrier;The active component includes platinum group element metal and cobalt.The preparation method provided by the present application uses de-ligand method, and cobalt is used to modify platinum group element in monatomic or cluster form, to prepare platinum group element-cobalt-indium oxide catalyst.The catalyst is relative to platinum group element supported on indium oxide catalyst, applied in carbon dioxide hydrogenation reaction, improves carbon dioxide conversion rate and the selectivity of methanol in product, with excellent catalytic activity, reaction activity, target product selectivity and reaction stability.Carbon dioxide conversion rate can reach 40%, and methanol selectivity reaches 90%.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide catalytic hydrogenation technology, and relates to a catalyst, particularly an indium oxide-based supported catalyst and its preparation method and application. Background Technology

[0002] The increasing concentration of greenhouse gases, particularly carbon dioxide, is leading to increasingly severe extreme weather phenomena globally. Developing carbon dioxide conversion pathways is crucial for addressing this problem. The hydrogenation of CO2 into high-value-added liquid fuels, especially methanol, is considered one of the most promising methods. Methanol can serve as a green fuel for ships, automobiles, and other transportation vehicles. Furthermore, methanol is an important raw material in the chemical industry, capable of being used in MTO reactions to convert into olefins, partially replacing the functions of petroleum. Therefore, utilizing carbon dioxide to convert into methanol is a vital link in building a "carbon-neutral cycle."

[0003] Indium oxide-based catalysts exhibit good anti-sintering properties and excellent methanol selectivity, and have been well studied in the catalytic hydrogenation of CO2. Indium oxide can support metals, and its oxygen vacancies have the ability to activate carbon dioxide. On the other hand, platinum group elements possess excellent hydrogen dissociation properties, and the synergistic effect of indium oxide and platinum group elements enables the preparation of methanol.

[0004] CN114405505A discloses a platinum-modified indium-based oxide catalyst, which exhibits high methanol selectivity but only achieves a carbon dioxide conversion rate of 15%. CN110479235A provides an indium oxide catalyst that achieves a carbon dioxide conversion rate of 29.3% and a methanol selectivity of 98.6% at a high temperature of 360°C, but this catalyst not only has an excessively high reaction temperature but also a long preparation process.

[0005] On the one hand, the synergistic effect between platinum group elements and indium oxide has not yet been better regulated; on the other hand, platinum group elements are expensive, and improving their reactivity is an important way to improve their cost-effectiveness. Therefore, finding better catalyst combinations and their preparation has become a priority, which is also the main problem this invention needs to solve. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an indium oxide-based supported catalyst, its preparation method, and its application. The indium oxide-based supported catalyst exhibits strong carbon dioxide activation and hydrogenolysis capabilities, and demonstrates excellent catalytic performance, reactivity, target product selectivity, and reaction stability in the process of preparing methanol from carbon dioxide hydrogenation.

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

[0008] In a first aspect, the present invention provides an indium oxide-based supported catalyst, the indium oxide-based supported catalyst comprising an indium oxide support and an active component supported on the indium oxide support;

[0009] The active components include platinum group metals and cobalt.

[0010] Compared to single-metal nanoparticles, bimetallic supported catalysts possess unique electronic effects and synergistic effects. This invention introduces a non-noble metal onto an indium oxide-supported noble metal catalyst, which can modify the noble metal and alter its electronic structure. It can also interact with the indium oxide support, optimizing oxygen vacancies and forming a unique active interface. This invention introduces cobalt via a ligand removal method, improving the formation rate and dispersibility of single atoms. The addition of cobalt can also form new active interfaces with platinum group metals and indium oxide, significantly enhancing the carbon dioxide activation and hydrogenolysis capabilities of the indium oxide-supported catalyst. Applied to the reaction of carbon dioxide hydrogenation to methanol, it exhibits excellent catalytic performance, reactivity, target product selectivity, and reaction stability, with a maximum carbon dioxide conversion rate of 40% and a methanol selectivity of 90%.

[0011] Preferably, the loading of the platinum group metal is 0.1wt%-10wt%, for example, it can be 0.1wt%, 0.5wt%, 1wt%, 3wt%, or 10wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] In this invention, the loading of platinum group elements refers to the percentage of platinum group elements by mass in the catalyst.

[0013] Preferably, the cobalt loading is 0.1wt%-10wt%, for example, it can be 0.1wt%, 0.5wt%, 1.5wt% or 10wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] In this invention, the cobalt loading refers to the percentage of cobalt by mass in the total catalyst.

[0015] Preferably, the platinum group metals include any one or a combination of at least two of ruthenium (Ru), rhodium (Rh), platinum (Pt), iridium (Ir), or osmium (Os). Typical but non-limiting combinations include combinations of platinum and ruthenium, platinum and rhodium, platinum and iridium, platinum and osmium, ruthenium, rhodium, iridium, and osmium, or ruthenium, rhodium, platinum, iridium, and osmium.

[0016] Preferably, in the indium oxide-based supported catalyst provided by the present invention, the cobalt element exists in the form of metal and / or oxide.

[0017] Preferably, in the indium oxide-based supported catalyst provided by the present invention, the cobalt element is aggregated in the form of single atoms or clusters.

[0018] In a second aspect, the present invention provides a method for preparing the indium oxide-based supported catalyst described in the first aspect, the method comprising the following steps:

[0019] (1) Preparation of platinum group element colloids: The pH value of the ethylene glycol solution of platinum group metal salts was adjusted to 7-13 using a sodium hydroxide ethylene glycol solution, and the solution was heated in a protective atmosphere for heat treatment. After cooling, the platinum group element colloids were obtained.

[0020] (2) Preparation of cobalt ammonia solution: Cobalt hydroxide or cobalt oxide is dissolved in ammonia water by stirring to obtain cobalt ammonia solution;

[0021] (3) The indium oxide support is dispersed in an organic medium, and then the platinum group element colloid obtained in step (1) is added to the dispersion system. After stirring and loading, solid-liquid separation is performed, followed by washing and drying to obtain the indium oxide supported platinum group element catalyst.

[0022] (4) The indium oxide supported platinum group element catalyst obtained in step (3) is dispersed in a liquid medium, and the cobalt ammonia solution obtained in step (2) is added. The mixture is mixed evenly and heated to dryness at a temperature of 40℃-200℃ to obtain the indium oxide-based supported catalyst.

[0023] Or include:

[0024] (a) Preparation of platinum group element colloids: The pH of the ethylene glycol solution of platinum group metal salts was adjusted to 7-13 using a sodium hydroxide ethylene glycol solution, and the solution was heated in a protective atmosphere for heat treatment. After cooling, the platinum group element colloids were obtained.

[0025] (b) Preparation of cobalt ammonia solution: Cobalt hydroxide or cobalt oxide is dissolved in ammonia water by stirring to obtain cobalt ammonia solution;

[0026] (c) The indium oxide support is dispersed in a liquid medium, and the cobalt ammonia solution obtained in step (b) is added. The mixture is stirred evenly and then heated to dryness at a temperature of 40℃-200℃ to obtain the indium oxide supported cobalt catalyst.

[0027] (d) The indium oxide-supported cobalt catalyst obtained in step (c) is dispersed in an organic medium, and then the platinum group element colloid obtained in step (a) is added to the dispersion system. After stirring and loading, solid-liquid separation is performed, followed by washing and drying to obtain the indium oxide-based supported catalyst.

[0028] The preparation method provided by this invention uses indium oxide as a support, and loads cobalt in the form of single atoms and clusters on the indium oxide support, and modifies the platinum group elements. This preparation method avoids the defect of forming large particles in the traditional impregnation method, makes the structure of the indium oxide-based supported catalyst easy to control, and exhibits very high activity, carbon dioxide conversion rate and methanol selectivity in the reaction of carbon dioxide hydrogenation to methanol.

[0029] When preparing the platinum group element colloid, the pH value is 7-13, for example, it can be 7, 8, 9, 10, 11, 12 or 13, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] For example, the heat treatment temperature is 120℃-190℃, such as 120℃, 130℃, 140℃, 150℃, 160℃, 180℃ or 190℃, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the platinum group metal salt includes any one or a combination of at least two of chloroplatinic acid, ruthenium trichloride, potassium hexachloroosmium tetroxide, iridium trichloride, or rhodium nitrate. Typical but non-limiting combinations include the combination of chloroplatinic acid and ruthenium trichloride, the combination of ruthenium trichloride and potassium hexachloroosmium tetroxide, the combination of iridium trichloride and ruthenium trichloride, the combination of chloroplatinic acid, ruthenium trichloride, and potassium hexachloroosmium tetroxide, the combination of chloroplatinic acid, ruthenium trichloride, potassium hexachloroosmium tetroxide, and iridium trichloride, or the combination of chloroplatinic acid, ruthenium trichloride, potassium hexachloroosmium tetroxide, iridium trichloride, and rhodium nitrate.

[0032] The platinum group metal salts in this invention include hydrates of platinum group metal salts and / or anhydrous compounds of platinum group metal salts.

[0033] Preferably, the protective atmosphere includes any one or a combination of at least two of hydrogen, nitrogen, helium, argon, neon, or krypton. Typical but non-limiting combinations include combinations of hydrogen and nitrogen, helium and neon, helium and argon, helium and krypton, helium and argon, or helium, neon, krypton, and argon.

[0034] Preferably, the organic medium includes any one or a combination of at least two of ethylene glycol, glycerol, propylene glycol, ethanol, or propanol. Typical but non-limiting combinations include combinations of ethylene glycol and glycerol, combinations of glycerol and propylene glycol, combinations of ethanol and propanol, combinations of ethylene glycol, propylene glycol, and acetone, or combinations of ethylene glycol, glycerol, propylene glycol, ethanol, and propanol.

[0035] Preferably, the liquid medium includes any one or a combination of at least two of water, methanol, ethanol, propanol or butanol. Typical but non-limiting combinations include a combination of methanol and ethanol, a combination of ethanol, propanol and butanol, or a combination of water, methanol, ethanol, propanol and butanol.

[0036] Preferably, the ammonia concentration includes 0.5% to 30%, for example, it can be 0.5%, 5%, 10%, 20%, 25% or 30%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Thirdly, the present invention provides an application of the indium oxide-based supported catalyst described in the first aspect, wherein the indium oxide-based supported catalyst is used for the catalytic hydrogenation of carbon dioxide.

[0038] Preferably, the application includes: setting an indium oxide supported catalyst and a reaction solvent in a reaction apparatus, purging carbon dioxide and hydrogen after gas washing, and heating to the reaction temperature to carry out the reaction.

[0039] Preferably, the reaction solvent includes any one or a combination of at least two of N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, or water. Typical but non-limiting combinations include a combination of N-methylpyrrolidone and dimethylformamide, a combination of dimethylformamide and dimethyl sulfoxide, or a combination of N-methylpyrrolidone, dimethylformamide, and dimethyl sulfoxide.

[0040] Preferably, the molar ratio of the indium oxide supported catalyst to carbon dioxide is 1:50-1:4000, for example, it can be 1:50, 1:100, 1:500, 1:1000, 1:2000, 1:3000 or 1:4000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] Preferably, the molar ratio of carbon dioxide to hydrogen is 1:1 to 1:10, for example, it can be 1:1, 1:3, 1:5, 1:6, 1:8 or 1:10, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the reaction temperature is 60℃-500℃, for example, it can be 60℃, 100℃, 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, 450℃ or 500℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0043] Preferably, the absolute pressure of the reaction is 0.1MPa-15MPa, for example, it can be 0.1MPa, 0.5MPa, 1MPa, 3MPa, 5MPa, 8MPa, 10MPa, 12MPa or 15MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] Preferably, the reaction apparatus includes any one of a high-pressure reactor, a fixed bed reactor, or a microchannel reactor.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) This invention introduces cobalt through the ligand removal method, which improves the formation rate and dispersion of single atoms. The addition of cobalt can also form a new active interface with platinum group metals and indium oxide, which significantly enhances the carbon dioxide activation and hydrogenolysis ability of indium oxide supported catalyst. When applied to the reaction of carbon dioxide hydrogenation to prepare methanol, it has excellent catalytic performance, reaction activity, target product selectivity and reaction stability. The carbon dioxide conversion rate can reach 40% and the methanol selectivity can reach 90%.

[0047] (2) The preparation method provided by the present invention uses indium oxide as a support, and loads cobalt in the form of single atoms, clusters or nanoparticles on the indium oxide support. The platinum group elements are electronically and geometrically modified. This preparation method avoids the defect of forming large particles in the traditional impregnation method, makes the structure of the indium oxide-based supported catalyst easy to control, and exhibits very high activity, carbon dioxide conversion rate and methanol selectivity in the reaction of carbon dioxide hydrogenation to methanol. Attached Figure Description

[0048] Figure 1 This is a TEM image of the indium oxide-based supported catalyst prepared in Example 1 of the present invention.

[0049] Figure 2 This is a high-resolution TEM image of the indium oxide-based supported catalyst prepared in Example 1 of this invention.

[0050] Figure 3 This is a CO2 temperature-programmed desorption curve comparing the indium oxide-based supported catalyst prepared in Example 1 of this invention with other catalysts.

[0051] Figure 4 This is a semi-in-situ XPS spectrum of the indium oxide-based supported catalyst prepared by the method of this invention.

[0052] Figure 5 HAADF-STEM and elemental mapping images of the indium oxide-based supported catalyst prepared in Example 1 of this invention. Detailed Implementation

[0053] 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.

[0054] Example 1

[0055] This embodiment provides an indium oxide-based supported catalyst 1.5Pt / In2O3-0.5Co, wherein the indium oxide-based supported catalyst comprises an indium oxide support with an average particle size of 100nm and an active component supported on the indium oxide support; the active component comprises Pt and Co, wherein the loading of Pt is 1.5wt% and the loading of Co is 0.5wt%.

[0056] The preparation method of the indium oxide-based supported catalyst provided in this embodiment includes the following steps:

[0057] (1) 0.1184 g of H2PtCl6·6H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 20 min until completely dissolved; a 0.25 mol / L sodium hydroxide solution in ethylene glycol was added to make the pH of the mixture 11, and the mixture was stirred for another 30 min to make the components in the mixture uniform; the mixture was heated to 160 °C in a nitrogen atmosphere, kept at the temperature for 3 h, and then naturally cooled to room temperature to obtain a brownish-brown, uniform and stable Pt colloid.

[0058] (2) Dissolve 0.0236g of cobalt hydroxide in 50mL of 20wt% ammonia water and stir until completely dissolved (the solution color changes from light pink to dark purple) to obtain a cobalt ammonia solution.

[0059] (3) 3.0 g of indium oxide support was uniformly dispersed in 150 mL of ethylene glycol. Under nitrogen atmosphere protection, the Pt colloid obtained in step (1) was slowly added dropwise and stirred until it was uniformly mixed. Then 250 mL of deionized water was added, and stirring was continued for 3 h. After filtration, washing and freeze drying, indium oxide supported platinum group element catalyst was obtained.

[0060] (4) The indium oxide supported platinum group element catalyst obtained in step (3) is dispersed in 150 mL of water, and then cobalt ammonia solution is slowly added dropwise and stirred until it is mixed evenly; first, it is heated at 60°C for 2 h, and then the temperature is raised to 100°C to dry, so as to obtain the indium oxide-based supported catalyst.

[0061] The TEM image of the indium oxide-based supported catalyst obtained in this embodiment is shown below. Figure 1 and Figure 2 As shown; HAADF-STEM and elemental mapping diagrams are as follows. Figure 5 As shown, by Figure 5It can be seen that platinum and cobalt are uniformly distributed on the indium oxide support, and no cobalt nanoparticles were observed, indicating that cobalt exists in a single-atom or cluster state, and the surface of the Pt particles is uniformly covered by cobalt; the CO2 temperature-programmed desorption curve is shown in the figure. Figure 3 As shown; the semi-in-situ XPS spectrum is as follows. Figure 4 As shown, by Figure 4 It can be seen that the Pt / In2O3 catalyst, the Co / In2O3-Pt catalyst, and the Pt / In2O3-Co catalyst obtained in this example show a significant shift in the binding energy around 71 eV. The peak position here corresponds to Pt 4f. 7 / 2 This proves that Pt exists in a metallic state. The Pt / In₂O₃ catalyst exhibits Pt₄f⁻. 7 / 2 Located at around 71.8, the binding energies of the other two catalysts shifted to lower values ​​after the introduction of Co, indicating that there is indeed electron transfer between Co and Pt, and that electrons are transferred from Co to Pt.

[0062] Example 2

[0063] This embodiment provides an indium oxide-based supported catalyst 1.5Ru / In2O3-0.5Co. Except that 0.1184g of H2PtCl6·6H2O is replaced with 0.0923g of RuCl3·3H2O, so that the active components are Ru and Co, with Ru loading of 1.5wt% and Co loading of 0.5wt%, everything else is the same as in Example 1.

[0064] Example 3

[0065] This embodiment provides an indium oxide-based supported catalyst 1.5Os / In2O3-0.5Co, except that 0.1184g of H2PtCl6·6H2O is replaced with 0.1046g of K2[OsCl6], so that the active components are Os and Co, with the loading of Os being 1.5wt% and the loading of Co being 0.5wt%. All other aspects are the same as in Example 1.

[0066] Example 4

[0067] This embodiment provides an indium oxide-based supported catalyst 1.5Ir / In2O3-0.5Co, except that 0.1184g of H2PtCl6·6H2O is replaced with 0.07g of IrCl3·3H2O, so that the active components are Ir and Co, with Ir loading of 1.5wt% and Co loading of 0.5wt%, and everything else is the same as in Example 1.

[0068] Example 5

[0069] This embodiment provides an indium oxide-based supported catalyst 1.5Rh / In2O3-0.5Co, except that 0.1184g of H2PtCl6·6H2O is replaced with 0.1286g of Rh(NO3)3·3H2O, so that the active components are Rh and Co, with Rh loading of 1.5wt% and Co loading of 0.5wt%, and everything else is the same as in Example 1.

[0070] Example 6

[0071] This embodiment provides an indium oxide-based supported catalyst 0.1Pt / In2O3-0.5Co, wherein the indium oxide-based supported catalyst comprises an indium oxide support with an average particle size of 100nm and an active component supported on the indium oxide support; the active component comprises Pt and Co, wherein the loading of Pt is 0.1wt% and the loading of Co is 0.5wt%.

[0072] The preparation method of the indium oxide-based supported catalyst provided in this embodiment includes the following steps:

[0073] (1) 0.03947 g of H2PtCl6·6H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 20 min until completely dissolved; a sodium hydroxide solution of 0.25 mL / L in ethylene glycol was added to make the pH of the mixture 11, and the mixture was stirred for another 30 min to make the components in the mixture uniform; the mixture was heated to 160 °C in a nitrogen atmosphere and kept at that temperature for 3 h, and then naturally cooled to room temperature to obtain a brownish-brown, uniform and stable Pt colloid.

[0074] (2) Dissolve 0.0236g of cobalt hydroxide in 50mL of 20wt% ammonia water and stir until completely dissolved (the solution color changes from light pink to dark purple) to obtain a cobalt ammonia solution.

[0075] (3) 3.0 g of indium oxide support was uniformly dispersed in 150 mol of ethylene glycol. Under nitrogen atmosphere protection, the Pt colloid obtained in step (1) was slowly added dropwise and stirred until it was uniformly mixed. Then 250 mL of deionized water was added, and stirring was continued for 3 h. After filtration, washing and freeze drying, indium oxide supported platinum group element catalyst was obtained.

[0076] (4) The indium oxide supported platinum group element catalyst obtained in step (3) is dispersed in 150 mL of water, and then cobalt ammonia solution is slowly added dropwise and stirred until it is mixed evenly; it is first heated at 60°C for 2 h, and then heated to 200°C to dry, to obtain the indium oxide-based supported catalyst.

[0077] Example 7

[0078] This embodiment provides an indium oxide-based supported catalyst 1Pt / In2O3-0.5Co, wherein the indium oxide-based supported catalyst comprises an indium oxide support with an average particle size of 100 nm and an active component supported on the indium oxide support; the active component comprises Pt and Co, wherein the loading amount of Pt is 1 wt% and the loading amount of Co is 0.5 wt%.

[0079] The preparation method of the indium oxide-based supported catalyst provided in this embodiment includes the following steps:

[0080] (1) 0.0789 g of H2PtCl6·6H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 20 min until completely dissolved; a 0.25 mol / L sodium hydroxide solution in ethylene glycol was added to make the pH of the mixture 11, and the mixture was stirred for another 30 min to make the components in the mixture uniform; the mixture was heated to 160 °C in a nitrogen atmosphere and kept at that temperature for 3 h, and then naturally cooled to room temperature to obtain a brownish-brown, uniform and stable Pt colloid.

[0081] (2) Dissolve 0.0236g of cobalt hydroxide in 50mL of 20wt% ammonia water and stir until completely dissolved (the solution color changes from light pink to dark purple) to obtain a cobalt ammonia solution.

[0082] (3) 3.0 g of indium oxide support was uniformly dispersed in 150 mL of ethylene glycol. Under nitrogen atmosphere protection, the Pt colloid obtained in step (1) was slowly added dropwise and stirred until it was uniformly mixed. Then 250 mL of deionized water was added, and stirring was continued for 3 h. After filtration, washing and freeze drying, indium oxide supported platinum group element catalyst was obtained.

[0083] (4) The indium oxide supported platinum group element catalyst obtained in step (3) is dispersed in 150 mL of water, and then cobalt ammonia solution is slowly added dropwise and stirred until it is mixed evenly; first, it is heated at 60°C for 2 h, and then the temperature is raised to 100°C to dry, so as to obtain the indium oxide-based supported catalyst.

[0084] Example 8

[0085] This embodiment provides an indium oxide-based supported catalyst 3Pt / In2O3-0.5Co. Except for changing the mass of H2PtCl6·6H2O in step (1) to 0.2368g, so that the Pt loading is 3wt%, everything else is the same as in Example 1.

[0086] Example 9

[0087] This embodiment provides an indium oxide-based supported catalyst 10Pt / In2O3-0.5Co. Except for changing the mass of H2PtCl·6H2O in step (1) to 0.7895g, so that the Pt loading is 10wt%, everything else is the same as in Example 1.

[0088] Example 10

[0089] This embodiment provides an indium oxide-based supported catalyst 1.5Pt / In2O3-0.1Co. Except for changing the mass of cobalt hydroxide in step (2) to 0.0047g, so that the loading of Co is 0.1wt%, everything else is the same as in Example 1.

[0090] Example 11

[0091] This embodiment provides an indium oxide-based supported catalyst 1.5Pt / In2O3-1Co. Except for changing the mass of cobalt hydroxide in step (2) to 0.0473g, so that the loading of Co is 1wt%, everything else is the same as in Example 1.

[0092] Example 12

[0093] This embodiment provides an indium oxide-based supported catalyst 1.5Pt / In2O3-3Co. Except for changing the mass of cobalt hydroxide in step (2) to 0.1429g, so that the loading of Co is 3wt%, everything else is the same as in Example 1.

[0094] Example 13

[0095] This embodiment provides an indium oxide-based supported catalyst 1.5Pt / In2O3-10Co. Except for changing the mass of cobalt hydroxide in step (2) to 0.4730g, so that the loading of Co is 10wt%, everything else is the same as in Example 1.

[0096] Example 14

[0097] This embodiment provides an indium oxide-based supported catalyst 0.5Co / In2O3-1.5Pt, wherein the indium oxide-based supported catalyst comprises an indium oxide support with an average particle size of 100nm and an active component supported on the indium oxide support; the active component comprises Pt and Co, wherein the loading of Pt is 1.5wt% and the loading of Co is 0.5wt%.

[0098] The preparation method of the indium oxide-based supported catalyst provided in this embodiment includes the following steps:

[0099] (1) 0.1184 g of H2PtCl6·6H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 20 min until completely dissolved; a 0.25 mol / L sodium hydroxide solution in ethylene glycol was added to make the pH of the mixture 11, and the mixture was stirred for another 30 min to make the components in the mixture uniform; the mixture was heated to 160 °C in a nitrogen atmosphere, kept at the temperature for 3 h, and then naturally cooled to room temperature to obtain a brownish-brown, uniform and stable Pt colloid.

[0100] (2) Dissolve 0.0236g of cobalt hydroxide in 50mL of 20wt% ammonia water and stir until completely dissolved (the solution color changes from light pink to dark purple) to obtain a cobalt ammonia solution.

[0101] (3) 3.0 g of indium oxide support was uniformly dispersed in 150 mL of water, and then cobalt ammonia solution was slowly added dropwise and stirred until it was uniformly mixed. The mixture was first heated at 60 °C for 2 h, and then heated to 100 °C to dry, to obtain indium oxide supported cobalt catalyst.

[0102] (4) The indium oxide-supported cobalt catalyst was dispersed in 150 mL of ethylene glycol. Under nitrogen atmosphere protection, the Pt colloid obtained in step (1) was slowly added dropwise and stirred until it was mixed evenly. Then, 250 mL of deionized water was added, and stirring was continued for 3 h. After filtration, washing and freeze drying, the indium oxide-based supported catalyst was obtained.

[0103] Example 15

[0104] This embodiment provides an indium oxide-based supported catalyst 1.5Pt / In2O3-0.5Co(500), where (500) indicates that the catalyst is prepared by calcination at 500°C. The indium oxide-based supported catalyst includes an indium oxide support with an average particle size of 100 nm and an active component supported on the indium oxide support. The active component includes Pt and Co, with Pt loading at 1.5 wt% and Co loading at 0.5 wt%.

[0105] The preparation method of the indium oxide-based supported catalyst provided in this embodiment includes the following steps:

[0106] (1) 0.1184 g of H2PtCl6·6H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 20 min until completely dissolved; a 0.25 mol / L sodium hydroxide solution in ethylene glycol was added to make the pH of the mixture 11, and the mixture was stirred for another 30 min to make the components in the mixture uniform; the mixture was heated to 160 °C in a nitrogen atmosphere, kept at the temperature for 3 h, and then naturally cooled to room temperature to obtain a brownish-brown, uniform and stable Pt colloid.

[0107] (2) Dissolve 0.0236 g of cobalt oxide in 50 mL of ammonia water with a concentration of 20 wt% to obtain a cobalt ammonia solution.

[0108] (3) 3.0 g of indium oxide support was uniformly dispersed in 150 mL of ethylene glycol. Under nitrogen atmosphere protection, the Pt colloid obtained in step (1) was slowly added dropwise and stirred until it was uniformly mixed. Then 250 mL of deionized water was added, and stirring was continued for 3 h. After filtration, washing and freeze drying, indium oxide supported platinum group element catalyst was obtained.

[0109] (4) The indium oxide supported platinum group element catalyst obtained in step (3) is dispersed in 150 mL of water, and then cobalt ammonia is slowly added dropwise and stirred until it is evenly mixed. It is first heated at 60°C for 2 hours, then heated to 100°C to dry, and then calcined at 500°C to obtain the indium oxide-based supported catalyst.

[0110] Comparative Example 1

[0111] This comparative example provides an indium oxide-based supported catalyst 0.1Pt / In2O3, wherein the indium oxide-based supported catalyst comprises an indium oxide support with an average particle size of 100nm and an active component supported on the indium oxide support; the active component comprises Pt, and the loading of Pt is 0.1wt%.

[0112] The preparation method of the indium oxide-based supported catalyst provided in this comparative example includes the following steps:

[0113] (1) 0.0395 g of H2PtCl6·6H2O was dissolved in 50 mL of ethylene glycol and stirred at room temperature for 20 min until completely dissolved; a 0.25 mol / L sodium hydroxide solution in ethylene glycol was added to make the pH of the mixture 11, and the mixture was stirred for another 30 min to make the components in the mixture uniform; the mixture was heated to 160 °C in a nitrogen atmosphere and kept at that temperature for 3 h, and then naturally cooled to room temperature to obtain a brownish-brown, uniform and stable Pt colloid.

[0114] (2) 3.0 g of indium oxide support was uniformly dispersed in 150 mL of ethylene glycol. Under nitrogen atmosphere protection, the Pt colloid obtained in step (1) was slowly added dropwise and stirred until it was uniformly mixed. Then 250 mL of deionized water was added, and stirring was continued for 3 h. After filtration, washing and freeze drying, indium oxide supported platinum group element catalyst was obtained.

[0115] Comparative Example 2

[0116] This comparative example provides an indium oxide-based supported catalyst 1.5Ru / In2O3, which is the same as Comparative Example 1 except that 0.0395g of H2PtCl6·6H2O is replaced with 0.0923g of RuCl3·3H2O, so that the active component is Ru and the loading of Ru is 1.5wt%.

[0117] Comparative Example 3

[0118] This comparative example provides an indium oxide-based supported catalyst 1.5Os / In2O3, except that 0.0395g of H2PtCl6·6H2O is replaced with 0.1046g of K2[OsCl6], making Os the active component, and the loading of Os is 1.5wt%. All other aspects are the same as those in Comparative Example 1.

[0119] Comparative Example 4

[0120] This comparative example provides an indium oxide-based supported catalyst 1.5Ir / In2O3, except that 0.0395g of H2PtCl6·6H2O is replaced with 0.07g of IrCl3·3H2O, making the active component Ir, and the loading of Ir is 1.5wt%. All other aspects are the same as those in Comparative Example 1.

[0121] Comparative Example 5

[0122] This comparative example provides an indium oxide-based supported catalyst 1.5Rh / In2O3, except that 0.0395g of H2PtCl6·6H2O is replaced with 0.1286g of Rh(NO3)3·3H2O, making Rh the active component, and the loading of Rh is 1.5wt%. All other aspects are the same as those in Comparative Example 1.

[0123] Comparative Example 6

[0124] This comparative example provides an indium oxide-based supported catalyst 1Pt / In2O3. Except for changing the mass of H2PtCl6·6H2O in step (1) to 0.0789g, so that the loading of Pt is 1wt%, everything else is the same as in Comparative Example 1.

[0125] Comparative Example 7

[0126] This comparative example provides an indium oxide-based supported catalyst 1.5Pt / In2O3. Except for changing the mass of H2PtCl6·6H2O in step (1) to 0.1184g, so that the Pt loading is 1.5wt%, everything else is the same as Comparative Example 1.

[0127] Comparative Example 8

[0128] This comparative example provides an indium oxide-based supported catalyst 3Pt / In2O3. Except for changing the mass of H2PtCl6·6H2O in step (1) to 0.2368g, so that the loading of Pt is 3wt%, everything else is the same as in Comparative Example 1.

[0129] Comparative Example 9

[0130] This comparative example provides an indium oxide-based supported catalyst 10Pt / In2O3. Except for changing the mass of H2PtCl6·6H2O in step (1) to 0.7895g, so that the loading of Pt is 10wt%, everything else is the same as in Comparative Example 1.

[0131] Comparative Example 10

[0132] This comparative example provides a Cu / In₂O₃ catalyst as described in Example 3 of CN117983225A, wherein the support is indium oxide and the Cu loading is 3 wt%. The specific preparation method includes:

[0133] Weigh 0.171g of copper nitrate trihydrate and 3.153g of indium nitrate pentahydrate and dissolve them in 30mL of deionized water to obtain solution A; weigh 1.916g of anhydrous sodium carbonate and dissolve it in 30mL of deionized water to obtain solution B; weigh 50mL of deionized water into a beaker and place it in a constant temperature water bath at 70℃. After the temperature stabilizes, slowly titrate solutions A and B simultaneously into the beaker containing 50mL of deionized water to obtain a precipitate mother liquor with a pH between 7 and 9; and allow it to settle at room temperature. The sample was aged under magnetic stirring for 4 hours; the aged sample was placed in a centrifuge and centrifuged at 7000 r / min for 5 min, washed repeatedly 3-5 times, and dried in an oven at 80℃ for 12 hours; the obtained sample was calcined in a muffle furnace at 500℃ for 3 hours; the obtained sample was reduced in 20H2 / Ar (the volume percentage of hydrogen in the mixed gas of hydrogen and argon is 20%) at 300℃ for 1 hour at a flow rate of 50 mL / min to obtain 3wt% Cu / In2O3.

[0134] Comparative Example 11

[0135] This comparative example uses a catalyst synthesis method disclosed in "Turning a Methanation Co Catalyst into an In-Co Methanol Producer" (ACS Catalysis. 9, 8, 2019, 6910-6918) to prepare the In@Co catalyst.

[0136] The active component of the catalyst obtained in this comparative example is Co, which has a core-shell structure, with a Co content of 80 wt% and an indium content of 20 wt%.

[0137] Comparative Example 12

[0138] This comparative example provides an indium oxide-based supported catalyst 0.5Co / In2O3, wherein the indium oxide-based supported catalyst comprises an indium oxide support with an average particle size of 100 nm and an active component supported on the indium oxide support; the active component comprises Co, and the loading amount of Co is 0.5 wt%.

[0139] The preparation method of the indium oxide-based supported catalyst provided in this comparative example includes the following steps:

[0140] (1) Dissolve 0.0236g of cobalt hydroxide in 50mL of ammonia water and stir until completely dissolved (the solution color changes from light pink to dark purple) to obtain a cobalt ammonia solution.

[0141] (2) 3.0 g of indium oxide support was uniformly dispersed in 150 mL of water, and then cobalt ammonia solution was slowly added dropwise and stirred until the mixture was uniform. The mixture was first heated at 60 °C for 2 h, and then heated to 100 °C to dry, to obtain indium oxide supported cobalt catalyst.

[0142] Performance characterization test results

[0143] In an autoclave, the catalysts obtained in the above examples and comparative examples were dispersed in N-methylpyrrolidone. Nitrogen gas was used for purging, repeated five times to remove air. Then, hydrogen gas at 4 MPa was introduced. The catalyst was first reduced to its metallic state, with the reduction temperature set at 160°C, the reduction time at 1.5 h, and the stirring speed at 500 rpm. After reduction, the residual gas in the autoclave was exhausted. A mixed gas at 5 MPa (H2 to CO2 molar ratio of 3:1), a catalyst to CO2 molar ratio of 1:650, a reaction temperature of 260°C, a reaction time of 8 h, and a stirring speed of 500 rpm were introduced. The CO2 conversion rate and selectivity were measured, and the results are shown in Table 1.

[0144] In addition, the catalyst obtained in Example 1 was placed in a microchannel reactor and a fixed-bed reactor to test its reaction performance. In the microchannel, 10g of catalyst was dispersed in 2L of N-methylpyrrolidone solvent. Using N-methylpyrrolidone as the solvent, the solvent was first injected into the reactor at a rate of 30mL / min for cleaning. Subsequently, a reducing gas of 1MPa was introduced, and the injection flow rate of the catalyst and solvent mixture was set at 30mL / min, the reduction temperature was 120℃, and the reduction was carried out for 1.5h. After reduction, the reducing gas was switched to a 1 MPa reaction mixture (H2 to CO2 molar ratio of 3:1), the reaction temperature was set to 160℃, and the reaction was carried out for 8 hours. In the fixed-bed reactor, 0.2 g of catalyst and 1 g of silica sand (SiC) were weighed and mixed evenly, then loaded into the constant temperature zone of the reaction tube and fixed with silica wool to prevent catalyst loss and backmixing. After the catalyst was loaded and the device was ensured to be leak-free, N2 was introduced into the reaction tube for 5 minutes (50 mL / min). The catalyst was heated to 160℃ at a heating rate of 10℃ / min. After reaching the specified temperature, the N2 was switched to the reducing gas H2 (50 mL / min), and the reduction was carried out for 1.5 hours. After reduction, the reducing gas was switched, the reaction temperature was set to 260℃, and the mixed gas (H2 to CO2 molar ratio of 3:1) was introduced at a flow rate of 30 mL / min. The results obtained from the tests in the microchannel and fixed-bed reactors are shown in Table 2.

[0145] Table 1

[0146]

[0147]

[0148]

[0149] Table 2

[0150]

[0151] In summary, on the one hand, this invention improves the carbon dioxide activation and hydrogenolysis capabilities of the indium oxide-based supported catalyst by introducing active platinum and cobalt components onto the indium oxide support to form a new active interface. When applied to the reaction of carbon dioxide hydrogenation to methanol, it exhibits excellent catalytic performance, reactivity, target product selectivity, and reaction stability, with a carbon dioxide conversion rate of up to 40% and a methanol selectivity of up to 90%. On the other hand, the preparation method provided by this invention uses indium oxide as a support and loads cobalt in the form of single atoms, clusters, or nanoparticles onto the indium oxide support, performing electronic and geometric modifications on the platinum group elements. This preparation method avoids the defects of traditional impregnation methods that result in larger particles, making the structure of the indium oxide-based supported catalyst easier to control, and exhibiting very high activity, carbon dioxide conversion rate, and methanol selectivity in the reaction of carbon dioxide hydrogenation to methanol.

[0152] 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. An indium oxide-based supported catalyst, characterized in that, The catalyst comprises an indium oxide support and an active component supported on the indium oxide support; the active component comprises platinum group metals and cobalt.

2. The indium oxide-based supported catalyst according to claim 1, characterized in that, The loading of the platinum group metals is 0.1 wt% to 10 wt%; the loading of the cobalt is 0.1 wt% to 10 wt%.

3. The indium oxide-based supported catalyst according to claim 1, characterized in that, The platinum group metals include any one or a combination of at least two of ruthenium, rhodium, platinum, iridium, or osmium.

4. A method for preparing the indium oxide-based supported catalyst according to claims 1-3, characterized in that, The preparation method includes the following steps: (1) Preparation of platinum group element colloids: The pH value of the ethylene glycol solution of platinum group metal salts was adjusted to 7-13 using a sodium hydroxide ethylene glycol solution, and the solution was heated in a protective atmosphere for heat treatment. After cooling, the platinum group element colloids were obtained. (2) Preparation of cobalt ammonia solution: Cobalt hydroxide or cobalt oxide is dissolved in ammonia water by stirring to obtain cobalt ammonia solution; (3) The indium oxide support is dispersed in an organic medium, and then the platinum group element colloid obtained in step (1) is added to the dispersion system. After stirring and loading, solid-liquid separation is performed, followed by washing and drying to obtain the indium oxide supported platinum group element catalyst. (4) The indium oxide supported platinum group element catalyst obtained in step (3) is dispersed in a liquid medium, and the cobalt ammonia solution obtained in step (2) is added. The mixture is mixed evenly and heated to dryness at a temperature of 40℃-200℃ to obtain the indium oxide-based supported catalyst. Or include: (a) Preparation of platinum group element colloids: The pH of the ethylene glycol solution of platinum group metal salts was adjusted to 7-13 using a sodium hydroxide ethylene glycol solution, and the solution was heated in a protective atmosphere for heat treatment. After cooling, the platinum group element colloids were obtained. (b) Preparation of cobalt ammonia solution: Cobalt hydroxide or cobalt oxide is dissolved in ammonia water by stirring to obtain cobalt ammonia solution; (c) The indium oxide support is dispersed in a liquid medium, and the cobalt ammonia solution obtained in step (b) is added. The mixture is stirred evenly and then heated to dryness at a temperature of 40℃-200℃ to obtain the indium oxide supported cobalt catalyst. (d) The indium oxide-supported cobalt catalyst obtained in step (c) is dispersed in an organic medium, and then the platinum group element colloid obtained in step (a) is added to the dispersion system. After stirring and loading, solid-liquid separation is performed, followed by washing and drying to obtain the indium oxide-based supported catalyst.

5. The preparation method according to claim 4, characterized in that, The platinum group metal salts include any one or a combination of at least two of chloroplatinic acid, potassium chloroplatinate, ruthenium trichloride, potassium hexachloroosmium tetroxide, iridium trichloride, or rhodium nitrate.

6. The preparation method according to claim 4, characterized in that, The protective atmosphere includes any one or a combination of at least two of the following gases: hydrogen, nitrogen, helium, argon, neon, or krypton.

7. The preparation method according to claim 4, characterized in that, The organic medium includes any one or a combination of at least two of ethylene glycol, glycerol, propylene glycol, ethanol, or propanol; And / or, the liquid medium includes any one or a combination of at least two of water, methanol, ethanol, propanol or butanol.

8. The application of an indium oxide-based supported catalyst according to any one of claims 1-3, characterized in that, The indium oxide-based supported catalyst is used for the catalytic hydrogenation of carbon dioxide.

9. The application according to claim 9, characterized in that, The application includes: setting an indium oxide supported catalyst and a reaction solvent in a reaction apparatus, purging carbon dioxide and hydrogen after gas washing, and heating to the reaction temperature to carry out the reaction. And / or, the reaction solvent includes any one or a combination of at least two of the following: N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, or water; And / or, the temperature range of the reaction is 60℃-500℃, and the pressure range is 0.1MPa-15MPa.

10. The application according to claim 8 or 9, characterized in that, The reaction apparatus includes any one of a high-pressure reactor, a fixed bed reactor, or a microchannel reactor.

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