Indium-based-carbon gap composition catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalyst synthesis, and particularly relates to an indium-based-carbon gap composition catalyst as well as a preparation method and application thereof. The indium-based-carbon gap composition catalyst comprises a carrier and an indium-based-carbon gap composition loaded on the carrier, the chemical structural formula of the indium-based-carbon gap composition is M3InCx, M is selected from one of Pt, Pd and Ni, and x is more than or equal to 0.5 and less than or equal to 1. According to the invention, acetylacetone metal salt and InCl are used as raw materials, and are subjected to hydrothermal reaction, washing, drying and other steps in an N, N-dimethylformamide or benzyl alcohol solvent according to a mass ratio of 3: 1 to prepare the InCl-metal complex. By changing the solvent, the product structure can be regulated and controlled, the obtained compound shows high activity and stability in catalytic reactions such as methanol water phase reforming hydrogen production, the preparation process is simple and convenient, high-temperature annealing is not needed, particle aggregation is effectively prevented, and a new way is provided for development of high-performance catalysts.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst synthesis, and in particular relates to an indium-based-carbon interstitial composite catalyst and a preparation method and application thereof. Background Art

[0002] In industrial catalytic processes, precious metal catalysts such as platinum (Pt) and palladium (Pd) occupy a key position due to their excellent physical and chemical properties. However, their large-scale application is limited by resource scarcity and stability challenges under extreme working conditions. The high cost of traditional precious metal catalysts and the problem of activity attenuation under harsh conditions such as high temperature and high pressure have seriously restricted the commercialization of emerging energy technologies, including hydrogen fuel cells. For example, the high cost of platinum catalysts in hydrogen fuel cells makes it difficult to popularize them in the automotive and distributed power generation fields; precious metal catalysts used in petrochemical hydrocracking reactions are prone to agglomeration and sintering under extreme working conditions, resulting in an irreversible decrease in catalytic activity. Therefore, it is particularly important to develop a simple method that can significantly improve the activity and stability of precious metal catalysts.

[0003] Noble metal-based interstitial compounds are novel interstitial compounds formed by precisely introducing light elements (such as C, N, O, and H) into the lattice interstices of noble metals (mainly platinum group metals such as Pt, Pd, Rh, and Ir). They possess excellent electronic structure and crystallographic properties, thus breaking through the performance bottleneck of traditional noble metal alloy catalysts. However, the preparation of noble metal-based interstitial compounds still faces the severe challenge of precise synthesis control. Traditional wet chemical methods are difficult to achieve atomic-level distribution control, while vapor deposition and high-temperature solid-phase methods rely on high temperature conditions (Nature Communications, 2024, 15(1): 9850; J. Am. Chem. Soc. 2025, 147, 20, 16786–16791), which easily induce metal particle agglomeration and carbon deposition side reactions, resulting in unstable catalyst performance. Although Guo et al. successfully synthesized palladium-carbon interstitial compounds using glucose-derived carbon sources through hydrothermal carbonization, this method has problems such as uneven carbon atom distribution and insufficient concentration control accuracy, which limits its practical application potential (Journal of Materials Chemistry A, 2019, 7(9): 4714-4720). Summary of the Invention

[0004] The purpose of the present invention is to provide an indium-based-carbon interstitial composite catalyst and its preparation method and application, thereby overcoming the shortcomings of the prior art. The present invention optimizes the solvent and introduces metal indium (In) to regulate the product structure, so that the resulting composite exhibits high activity and stability in catalytic reactions such as methanol aqueous phase reforming to produce hydrogen. The preparation process is simple, no high-temperature annealing is required, and particle agglomeration is effectively prevented, providing a new approach for the development of high-performance catalysts.

[0005] In order to achieve the above object, the technical solution of the present invention is: In the first aspect, the present invention provides an indium-carbon interstitial composite catalyst, comprising a carrier and an indium-carbon interstitial composite supported on the carrier, wherein the chemical structure of the indium-carbon interstitial composite is M3InC x , wherein M is selected from one of Pt, Pd and Ni, and 0.5≤x≤1.

[0006] The indium-based-carbon interstitial composite catalyst provided by the present invention precisely regulates the indium-carbon interaction, has atomically dispersed active centers, an adjustable electronic structure, a stable carrier interface, and an efficient mass transfer / conductive network. These characteristics enable it to show significant potential in the fields of energy conversion and environmental catalysis.

[0007] In some other embodiments, the support is selected from at least one of a metal oxide, a carbon-based support, a ceramic support, and boron nitride; Optionally, the carrier is selected from at least one of alumina, silica, titania, cerium oxide, zirconium oxide, activated carbon, molecular sieve carrier, carbon nanotubes, acetylene black and g-C3N4; Further optionally, the carrier is selected from at least one of silica, acetylene black and g-C3N4.

[0008] The carriers selected in the present invention all have high specific surface areas, provide dispersion sites for active components, and significantly influence the activity, selectivity and stability of the catalyst through physical and chemical effects.

[0009] In some other embodiments, the chemical formula of the indium-carbon interstitial composite is M3InC x , where M is selected from Pt, Pd, and Ni, and x is any value between 0.5 and 1, such as 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0. Optionally, x is 0.5 and 1. x corresponds to different carbon filling ratios, affecting the electronic conductivity and chemical stability of the material. Pt has a high d electron density, optimizes H adsorption, and has strong CO tolerance. Pd has high selectivity for C=C bond hydrogenation and synergistically promotes C-C coupling with In. Ni has low cost and a tunable d band center.

[0010] Alternatively, the loading amount of the indium-based-carbon interstitial composite is 0.1-3.0 wt%; it can also be adjusted according to the type of carrier, catalytic activity, selectivity and economic conditions, such as the loading amount of the indium-based-carbon interstitial composite is any one of 0.2 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, and 3.0 wt%.

[0011] Optionally, the chemical formula of the indium-carbon interstitial composite is Pt3InC 0.5 , Pd3InC and Ni3InC 0.5 .

[0012] In the indium-carbon interstitial composite of this composition, smaller carbon atoms (C) are embedded in the lattice gaps composed of metal (M) and indium (In). Pt / Pd / Ni forms metallic bonds (M-In) with In to regulate the d electron density, while the MC bond may enhance the carrier interaction and optimize the adsorption / activation ability. The M-In-C ternary synergy combines metal activity and carrier stability. The x value can adjust the balance between conductivity and defect activity. x = 0.5 or 1 corresponds to different carbon filling rates, which affects the electronic conductivity and chemical stability of the material. For example, when x = 1 (such as Pt3InC): carbon atoms fill the interstitial positions, the structure is more compact, and the conductivity is enhanced; when x = 0.5 (such as PtInC 0.5 ): Partial filling may introduce defect sites and increase the exposure of active sites.

[0013] In a second aspect, the present invention provides a method for preparing the indium-carbon interstitial composite catalyst described in the first aspect, comprising the following steps: The metal precursor, indium chloride and a carrier are added into a solvent and stirred to prepare a mixed solution; the mixed solution is subjected to a hydrothermal reaction, and an indium-based-carbon interstitial composite catalyst is obtained after the reaction is completed.

[0014] In some other embodiments, the molar ratio of the metal salt of acetylacetonate to indium chloride is 3:1; Alternatively, the concentration of indium chloride in the solvent is 1.0-1.5 mol / L; Alternatively, the mass ratio of indium chloride to the carrier is 0.1-3.0 wt%.

[0015] In some other embodiments, the metal precursor is selected from at least one of platinum acetylacetonate, palladium acetylacetonate, nickel acetylacetonate, and chloroplatinic acid; Alternatively, the solvent is selected from at least one of N,N-dimethylformamide and benzyl alcohol. These two solvents can also serve as reducing agents. The amount of solvent used must strike a balance between complete reduction, particle dispersibility, and system stability. Excessive amounts of solvent can dilute the reaction concentration and increase post-processing costs. Excessive amounts can cause a sudden increase in the viscosity of the reaction system (e.g., in high-concentration metal salt solutions), leading to uneven stirring, localized overheating, severe agglomeration, incomplete reduction, and the initiation of side reactions (e.g., incomplete carbonization of the carbon source).

[0016] The reaction described in this paper is an in-situ deposition-based slow reduction process, in which the choice of solvent type (which directly influences the reducing agent's reducing power) and reaction temperature are key control variables. Systematic experimental verification has confirmed the selection of N,N-dimethylformamide / benzyl alcohol as the reaction medium, which serves as both solvent and reducing agent. By modulating the synergistic effects of carbonyl and amine groups within the molecule, it achieves controlled reduction and directional deposition of metal ions. The reactants, platinum acetylacetonate and InCl₃, must be mixed in a strict 3:1 molar ratio to ensure stoichiometric balance.

[0017] During the reaction, N,N-dimethylformamide can be thermally decomposed into HN(CH3)2 and CO as follows:

[0018] Benzyl alcohol is heated in solution to produce benzene and CO as follows:

[0019] The present invention has significant advantages. Its indium-carbon interstitial compound catalyst (Pt3InC 0.5 , Pd3InC and Ni3InC 0.5 The preparation process of the catalyst is simple and easy, and does not require high-temperature annealing, thereby effectively preventing the occurrence of particle agglomeration and ensuring the excellent performance and stability of the catalyst.

[0020] In some other embodiments, the stirring speed is 800-1200 r / min, and the stirring time is 5-30 min; Alternatively, the hydrothermal reaction temperature is 180-220°C, the heating rate is 5-15°C / min, and the holding time is 20-30 h; Optionally, the temperature of the hydrothermal reaction is 210°C, the heating rate is 10°C / min, and the holding time is 24h; Alternatively, after the reaction is completed, the product is sequentially washed, centrifuged and vacuum dried, and the washing solvent is anhydrous ethanol; The centrifugal speed is 10000-15000 rpm, and the number of centrifugation is 2-5 times; the vacuum drying temperature is 55-65°C, and the drying time is 3-6 hours; Optionally, the centrifugal speed is 11,000 rpm, the number of centrifugation is 3 times; the vacuum drying temperature is 60° C., and the drying time is 5 hours.

[0021] The reaction was carried out in a high-pressure hydrothermal autoclave, the system temperature was set to 210°C, and the reaction was kept at a constant temperature for 24 hours. This parameter combination was verified by multiple sets of comparative experiments and can achieve the highest yield and optimal crystallinity of the target product, which is the optimal synthesis condition for the reaction.

[0022] In a third aspect, the present invention provides the use of the indium-carbon interstitial composite catalyst described in the first aspect in hydrogen fuel cells, hydrogenation reactions, and alcohol oxidation reactions; Optionally, it can be used in the liquid phase reforming of methanol to produce hydrogen.

[0023] In a fourth aspect, the present invention provides a method for producing hydrogen by liquid-phase reforming of methanol, using the indium-based-carbon interstitial composite catalyst described in the first aspect.

[0024] In some other embodiments, methanol water is used as the reaction substrate, the reaction atmosphere is nitrogen, the reaction pressure is 0.5-1.5 MPa, the reaction temperature is 140-200° C., the reaction time is 30-90 min, and the catalyst addition amount is 8-12 mg.

[0025] Beneficial effects of the present invention: (1) The indium-carbon interstitial composite catalyst provided by the present invention precisely regulates the indium-carbon interaction and has atomically dispersed active centers, adjustable electronic structure, stable carrier interface and efficient mass transfer / conductive network. These characteristics make it show significant potential in the fields of energy conversion and environmental catalysis.

[0026] (2) The reaction of the present invention is an in-situ deposition slow reduction process, in which the choice of solvent type (directly related to the reducing ability of the reducing agent) and reaction temperature are the key control variables. Systematic experimental verification has shown that N,N-dimethylformamide / benzyl alcohol is selected as the reaction medium, which has the dual functions of solvent and reducing agent. It can achieve controlled reduction and directional deposition of metal ions by regulating the synergistic effect of carbonyl and amine groups within the molecule.

[0027] (3) The indium-based-carbon interstitial composite catalyst prepared by the present invention exhibits high activity and stability in catalytic reactions such as methanol aqueous phase reforming to produce hydrogen.

[0028] In summary, the indium-based-carbon interstitial composite catalyst prepared by the present invention solves problems such as the scarcity of precious metal resources and performance bottlenecks. By changing the solvent, the product structure can be regulated. The obtained composite exhibits high activity and stability in catalytic reactions such as methanol aqueous phase reforming to produce hydrogen. Its preparation process is simple, does not require high-temperature annealing, and effectively prevents particle agglomeration. It provides a new approach for the development of high-performance catalysts, promotes technological progress in multiple fields such as energy, electronics, and chemical industry, and has important scientific significance and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0030] Figure 1 TEM and HRTEM images of the products prepared in Example 1 and Comparative Example 1 of the present invention; wherein a is a TEM image of the product prepared in Example 1, b is an HRTEM image of the product prepared in Example 1, and c is an HRTEM image of the product prepared in Comparative Example 1; Figure 2 The EDS images of the products prepared in Example 1 and Comparative Example 1 of the present invention are shown; Figure 3 Mapping diagrams of the products prepared in Example 1 and Comparative Example 1 of the present invention; Figure 4 The X-ray powder diffraction analysis patterns of the products prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention are as follows; Figure 5 This is the X-ray powder diffraction analysis pattern of the products prepared in Example 6 and Example 7 of the present invention; Figure 6 This is the X-ray powder diffraction analysis pattern of the products prepared in Example 8, Example 9, and Comparative Example 4 of the present invention; Figure 7 Diffuse reflectance Fourier transform infrared spectroscopy (DRIFT) spectra of CH3OH adsorbed on the products prepared in Example 1 and Comparative Example 1 of the present invention; in, Figure 1-Figure 7 The sample prepared in Example 1 is Pt3InC 0.5 / SiO2, the sample prepared in Example 2 is Pd3InC / SiO2, and the sample prepared in Example 3 is Ni3InC 0.5 / SiO2, and the samples prepared in Examples 4 and 5 were Pt3InC with different loading amounts (0.5 wt% and 0.2 wt%). 0.5 / SiO2, the sample prepared in Example 6 is Pt3InC 0.5 / C, the sample prepared in Example 7 is Pt3InC 0.5 / g-C3N4, the sample prepared in Example 8 is Pt3InC 0.5 / SiO2-H2PtCl6, the sample prepared in Example 9 is Pt3InC 0.5 / SiO2-PhCH2OH, the product prepared in Comparative Example 1 is Pt3In / SiO2, the product prepared in Comparative Example 2 is Pd3In / SiO2, the product prepared in Comparative Example 3 is Ni3In / SiO2, the product prepared in Comparative Example 4 is Pt / SiO2, and the product prepared in Comparative Example 5 is 0.2 wt% Pt3In / SiO2. DETAILED DESCRIPTION

[0031] Those skilled in the art will appreciate that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the examples were performed under conventional conditions or manufacturer's recommended conditions. Components used without manufacturer's indication are commercially available conventional products.

[0032] Noble metal-based interstitial compounds, formed by precisely introducing light elements (such as C, N, O, and H) into the lattice interstices of noble metals (primarily platinum group metals such as Pt, Pd, Rh, and Ir), possess superior electronic structure and crystallographic properties, thus overcoming the performance bottlenecks of traditional noble metal alloy catalysts. The sub-angstrom atomic size of the light elements allows them to seamlessly integrate into the noble metal lattice interstices. Simultaneously, the significant electronegativity difference drives the hybridization of s and pd orbitals, triggering lattice expansion and strain modulation, which in turn alters the d-band electronic structure and enhances catalytic activity. This structural design enables noble metal interstitial compounds to exhibit performance far superior to that of traditional catalysts in key catalytic processes such as hydrogenation and alcohol oxidation.

[0033] However, current methods for preparing precious metal-based interstitial compounds cannot achieve precise synthesis control and require stringent preparation conditions. High temperatures, for example, can easily lead to metal particle agglomeration and carbon deposition, resulting in unstable catalyst performance. This invention, by optimizing the solvent and introducing indium (In) to manipulate the product structure, enables the resulting compound to exhibit high activity and stability in catalytic reactions such as methanol aqueous reforming to produce hydrogen. This method features a simple preparation process, eliminates the need for high-temperature annealing, and effectively prevents particle agglomeration, providing a new approach for the development of high-performance catalysts.

[0034] An embodiment of the present invention provides an indium-based-carbon interstitial composite catalyst, comprising a carrier and an indium-based-carbon interstitial composite supported on the carrier. The chemical structure of the indium-based-carbon interstitial composite is M3InCx, wherein M is selected from one of Pt, Pd and Ni, and 0.5≤x≤1.

[0035] Some other embodiments of the present invention provide a method for preparing an indium-based-carbon interstitial composite catalyst, comprising the following steps: The metal precursor, indium chloride and a carrier are added into a solvent and stirred to prepare a mixed solution; the mixed solution is subjected to a hydrothermal reaction, and an indium-based-carbon interstitial composite catalyst is obtained after the reaction is completed.

[0036] An indium-based-carbon interstitial composite catalyst Pt3InC 0.5 The preparation method of the catalyst comprises the following steps: At room temperature and pressure, accurately weigh platinum acetylacetonate (0.1128 mol), InCl3 (0.0376 mol), and the carrier (adjust the amount according to the loading amount) into a 50 mL sample bottle, then add 30 mL of N,N-dimethylformamide / benzyl alcohol. Place a type B magnetic stirrer in the sample bottle and stir continuously at 800-1000 r / min on a stirrer for 20-30 min to fully dissolve the metal precursor and form a uniform mixed solution. After stirring, the mixed solution is transferred to a 100 mL PPL hydrothermal autoclave, placed in an oven and heated to 210°C for 24 hours. After the reaction is completed and cooled to room temperature, the mixed solution is transferred to a centrifuge tube, washed with anhydrous ethanol as a detergent, and centrifuged three times at 11,000 rpm. Finally, it is placed in a vacuum oven and dried at 60°C for 5 hours to obtain the target product.

[0037] Pd3InC and Ni3InC 0.5 Preparation method: During the material synthesis process, platinum acetylacetonate can be used as a variable precursor and replaced with other acetylacetonate metal salts for experiments. Specifically, when preparing Pd3InC, the raw material platinum acetylacetonate is replaced with palladium acetylacetonate; when preparing Ni3InC 0.5 When preparing the reaction, platinum acetylacetonate was replaced with nickel acetylacetonate. The substituted acetylacetonate metal salt and InCl3 were precisely dosed in a 3:1 molar ratio to ensure the stoichiometric accuracy of the reaction system. Aside from the changes in precursors and feed components, all other synthetic steps, including but not limited to reaction temperature, reaction time, solvent selection, stirring rate, and post-processing procedures, were strictly followed according to the original experimental protocol to ensure consistency and reproducibility of experimental conditions.

[0038] Some other embodiments of the present invention provide applications of indium-carbon interstitial composite catalysts in hydrogen fuel cells, hydrogenation reactions, and alcohol oxidation reactions; optionally, applications in methanol liquid-phase reforming hydrogen production reactions.

[0039] Some other embodiments of the present invention provide a method for producing hydrogen by liquid-phase reforming of methanol, using the indium-based-carbon interstitial composite catalyst described in the first aspect.

[0040] The technical solution of the present invention is further described below in conjunction with specific embodiments: Example 1 A method for preparing an indium-based-carbon interstitial composite catalyst comprises the following steps: (1) At room temperature and pressure, accurately weigh platinum acetylacetonate (0.1128 mol), InCl3 (0.0376 mol) and SiO2 carrier (the mass ratio of indium chloride to carrier is 1.0 wt%, i.e., the loading amount is 1.0 wt%) and place them in a 50 mL sample bottle. Then add 30 mL of N,N-dimethylformamide, place a type B magnetic stirrer in the sample bottle, and place it on a stirrer and stir continuously at 1000 r / min for 25 min to fully dissolve the metal precursor and form a uniform mixed solution.

[0041] (2) After stirring, the mixed solution was transferred to a 100 mL para-polyphenol (PPL) hydrothermal reactor, placed in an oven and heated to 210 °C for 24 hours.

[0042] (3) After the reaction is completed, the mixture is cooled to room temperature and transferred to a centrifuge tube. After washing and centrifuging at 11,000 rpm for three times with anhydrous ethanol, the mixture is placed in a vacuum oven and dried at 60 °C for 5 hours. The obtained product is labeled as Pt3InC 0.5 / SiO2.

[0043] Example 2 A method for preparing an indium-based-carbon interstitial composite catalyst comprises the following steps: (1) At room temperature and pressure, accurately weigh acetylacetonate palladium (0.1128 mol), InCl3 (0.0376 mol) and SiO2 carrier (the mass ratio of indium chloride to carrier is 1.0 wt%, i.e., the loading amount is 1.0 wt%) and place them in a 50 mL sample bottle. Then, add 30 mL of N,N-dimethylformamide. Place a type B magnetic stirrer in the sample bottle and stir it on a stirrer at 1000 r / min for 25 min to fully dissolve the metal precursor and form a uniform mixed solution.

[0044] (2) After stirring, transfer the mixed solution into a 100 mL PPL hydrothermal kettle, place it in an oven and heat it to 210 °C for 24 hours.

[0045] (3) After the reaction is completed and the temperature is lowered to room temperature, the mixed solution is transferred to a centrifuge tube, washed with anhydrous ethanol and centrifuged at 11,000 rpm for three times. Finally, it is placed in a vacuum oven and dried at 60 °C for 5 hours. The obtained product is labeled as Pd3InC / SiO2.

[0046] Example 3 A method for preparing an indium-based-carbon interstitial composite catalyst comprises the following steps: (1) At room temperature and pressure, accurately weigh nickel acetylacetonate (0.1128 mol), InCl3 (0.0376 mol) and SiO2 carrier (the mass ratio of indium chloride to carrier is 1.0 wt%, i.e., the loading amount is 1.0 wt%) and place them in a 50 mL sample bottle. Then, add 30 mL of N,N-dimethylformamide. Place a type B magnetic stirrer in the sample bottle and place it on a stirrer and stir continuously at 1000 r / min for 25 min to fully dissolve the metal precursor and form a uniform mixed solution.

[0047] (2) After stirring, the mixed solution was transferred to a 100 mL PPL hydrothermal kettle, placed in an oven and heated to 210 °C for 24 hours.

[0048] (3) After the reaction is completed and the mixture is cooled to room temperature, the mixed solution is transferred to a centrifuge tube, washed with anhydrous ethanol and centrifuged at 11,000 rpm for 3 times, and finally placed in a vacuum oven and dried at 60 °C for 5 hours. The obtained product is labeled as Ni3InC 0.5 / SiO2.

[0049] Example 4 The difference from Example 1 is that in step (1), the mass ratio of indium chloride to the carrier is 0.5 wt%, that is, the loading amount is 0.5 wt%. The other preparation methods are consistent with Example 1.

[0050] Example 5 The difference from Example 1 is that in step (1), the mass ratio of indium chloride to the carrier is 0.2 wt%, that is, the loading amount is 0.2 wt%. The other preparation methods are consistent with Example 1.

[0051] Example 6 The difference from Example 1 is that in step (1), acetylene black (C) is used to replace the SiO2 carrier. The other preparation methods are consistent with those of Example 1. The obtained product is marked as Pt3InC 0.5 / C.

[0052] Example 7 The difference from Example 1 is that in step (1), carbon nitride (g-C3N4) is used to replace the SiO2 carrier. The other preparation methods are consistent with those of Example 1. The obtained product is marked as Pt3InC 0.5 / g-C3N4.

[0053] Example 8 The difference from Example 1 is that in step (1), chloroplatinic acid (H2PtCl6) is used to replace platinum acetylacetonate. The other preparation methods are consistent with those of Example 1. The obtained product is marked as Pt3InC 0.5 / SiO2-H2PtCl6.

[0054] Example 9 The difference from Example 1 is that in step (1), benzyl alcohol (PhCH2OH) is used to replace N,N-dimethylformamide. The other preparation methods are consistent with those of Example 1. The obtained product is labeled as Pt3InC 0.5 / SiO2-PhCH2OH.

[0055] Comparative Example 1 A method for preparing an indium-based composite catalyst comprises the following steps: (1) At room temperature and pressure, accurately weigh platinum acetylacetonate (0.1128 mol), InCl3 (0.0376 mol) and SiO2 carrier (the mass ratio of indium chloride to carrier is 1.0 wt%, i.e., the loading amount is 1.0 wt%) and add them into a 50 mL sample bottle. Then add 30 mL of ethylene glycol. Place a type B magnetic stirrer in the sample bottle and place it on a stirrer and stir continuously at 1000 r / min for 25 min to fully dissolve the metal precursor and form a uniform mixed solution.

[0056] (2) After stirring, transfer the mixed solution into a 100 mL PPL hydrothermal kettle, place it in an oven and heat it to 210 °C for 24 hours.

[0057] (3) After the reaction is completed and the temperature is lowered to room temperature, the mixed solution is transferred to a centrifuge tube, washed with anhydrous ethanol and centrifuged at 11,000 rpm for three times. Finally, it is placed in a vacuum oven and dried at 60 °C for 5 hours. The obtained product is labeled as Pt3In / SiO2.

[0058] Comparative Example 2 A method for preparing an indium-based composite catalyst comprises the following steps: (1) At room temperature and pressure, accurately weigh acetylacetonate palladium (0.1128 mol), InCl3 (0.0376 mol) and SiO2 carrier (the mass ratio of indium chloride to carrier is 1.0 wt%, i.e., the loading amount is 1.0 wt%) and place them in a 50 mL sample bottle. Then add 30 mL of ethylene glycol, place a type B magnetic stirrer in the sample bottle, and place it on a stirrer and stir continuously at 1000 r / min for 25 min to fully dissolve the metal precursor and form a uniform mixed solution.

[0059] (2) After stirring, transfer the mixed solution into a 100 mL PPL hydrothermal kettle, place it in an oven and heat it to 210 °C for 24 hours.

[0060] (3) After the reaction is completed and the temperature is lowered to room temperature, the mixed solution is transferred to a centrifuge tube, washed with anhydrous ethanol and centrifuged at 11,000 rpm for three times. Finally, it is placed in a vacuum oven and dried at 60 °C for 5 hours. The obtained product is labeled as Pd3In / SiO2.

[0061] Comparative Example 3 A method for preparing an indium-based composite catalyst comprises the following steps: (1) At room temperature and pressure, accurately weigh nickel acetylacetonate (0.1128 mol), InCl3 (0.0376 mol) and SiO2 carrier (the mass ratio of indium chloride to carrier is 1.0 wt%, i.e., the loading amount is 1.0 wt%) and place them in a 50 mL sample bottle. Then, add 30 mL of ethylene glycol. Place a type B magnetic stirrer in the sample bottle and place it on a stirrer and stir continuously at 1000 r / min for 25 min to fully dissolve the metal precursor and form a uniform mixed solution.

[0062] (2) After stirring, transfer the mixed solution into a 100 mL PPL hydrothermal kettle, place it in an oven and heat it to 210 °C for 24 hours.

[0063] (3) After the reaction is completed and the temperature is cooled to room temperature, the mixed solution is transferred to a centrifuge tube, washed with anhydrous ethanol and centrifuged at 11,000 rpm for three times. Finally, it is placed in a vacuum oven and dried at 60 °C for 5 hours. The obtained product is labeled Ni3In / SiO2.

[0064] Comparative Example 4 The difference from Example 1 is that in step (1), InCl3 is not added, and platinum acetylacetonate and SiO2 carrier are directly added to 30 mL of N,N-dimethylformamide with a loading amount of 1.0 wt%. The other preparation methods are consistent with Example 1, and the obtained product is labeled as Pt / SiO2.

[0065] Comparative Example 5 The difference from Example 1 is that the mass ratio of indium chloride to the carrier is 0.2 wt %, that is, the loading amount is 0.2 wt %. The other preparation methods are consistent with those of Comparative Example 1.

[0066] Performance Testing The samples obtained in the embodiment of the present invention and comparative example 1 were subjected to TEM, HRTEM, EDS, Mapping, DRIFT and X-ray powder diffraction test results. Figure 1-Figure 7 As shown, the sample prepared in Example 1 is Pt3InC 0.5 / SiO2, the sample prepared in Example 2 is Pd3InC / SiO2, and the sample prepared in Example 3 is Ni3InC 0.5 / SiO2, and the samples prepared in Examples 4 and 5 were Pt3InC with different loading amounts (0.5 wt% and 0.2 wt%). 0.5 / SiO2, the sample prepared in Example 6 is Pt3InC 0.5 / C, the sample prepared in Example 7 is Pt3InC 0.5 / g-C3N4, the sample prepared in Example 8 is Pt3InC 0.5 / SiO2-H2PtCl6, the sample prepared in Example 9 is Pt3InC 0.5 / SiO2-PhCH2OH, the product prepared in Comparative Example 1 was Pt3In / SiO2, the product prepared in Comparative Example 2 was Pd3In / SiO2, the product prepared in Comparative Example 3 was Ni3In / SiO2, the product prepared in Comparative Example 4 was Pt / SiO2, and the product prepared in Comparative Example 5 was 0.2 wt% Pt3In / SiO2. The specific test results are as follows: Figure 1 TEM and HRTEM images of the products prepared in Example 1 and Comparative Example 1 of the present invention, wherein a is a TEM image of the product prepared in Example 1, b is a HRTEM image of the product prepared in Example 1, and c is a HRTEM image of the product prepared in Comparative Example 1. Figure 1 As can be seen from a in Example 1, the particle size of the product prepared is 2-4 nm; Figure 1 As can be seen from b and c, the product Pt3InC prepared in Example 1 0.5 The interplanar spacing of the Pt3In / SiO2 alloy is 0.209 nm, which is smaller than the interplanar spacing of 0.233 nm for the Pt3In / SiO2 product prepared in Comparative Example 1. This lattice parameter difference stems from the interstitial structure formed by the embedding of carbon atoms into the Pt-In alloy lattice, which triggers lattice microstructural adjustments and demonstrates the successful construction of the indium-carbon interstitial composite.

[0067] Figure 2The EDS diagrams of the products prepared in Example 1 and Comparative Example 1 of the present invention are shown in FIG. Figure 2 It can be seen that the ratio of the Pt to In element content in the product prepared in Example 1 and the ratio of the Pt to In element content in the product prepared in Comparative Example 1 are both close to 3:1.

[0068] Figure 3 Mapping diagram of the products prepared in Example 1 and Comparative Example 1 of the present invention; Figure 3 It can be seen that the elements in the products prepared in Example 1 and Comparative Example 1 are dispersed more evenly without agglomeration. 0.5 In the Pt3In / SiO2 sample, Pt, In, and C elements are uniformly dispersed within the SiO2-supported nanoparticle region, confirming the atomically uniform distribution of the carbon interstitial compound. In contrast, the carbon element mapping profile of the Pt3In / SiO2 sample from Comparative Example 1 shows no characteristic distribution profile, consistent with design expectations. Figure 4 The X-ray powder diffraction analysis patterns of the products prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention are as follows; Figure 4 It can be seen that Pt3InC 0.5 / SiO2 in 2 θ =39°, 45°, 51° show characteristic diffraction peaks of (111), (200), and (210) crystal planes, which are similar to those of Pt3InC 0.5 Standard card (PDF No.28-0472) highly matched; Pd3InC / SiO2 at 2 θ =39°, 45° appear (111), (200) crystal plane characteristic peaks, corresponding to Pd3InC standard card (PDF No.28-0470); Ni3InC 0.5 / SiO2 in 2 θ =33°, 41°, 48°, 54° show characteristic peaks of (110), (111), (200), and (210) crystal planes, which are similar to those of Ni3InC 0.5 The above data show that the method of the present invention successfully prepared indium-carbon interstitial composites and showed good universality in different metal systems. 0.5 / SiO2, Pd3InC / SiO2, Ni3InC 0.5 The characteristic diffraction peaks of / SiO2 match well with the corresponding standard cards, further verifying that we have successfully synthesized indium-based-carbon interstitial composites and traditional alloy compounds.

[0069] Figure 5The X-ray powder diffraction analysis patterns of the products prepared in Example 6 and Example 7 of the present invention are as follows; Figure 4 、 Figure 5 It can be seen that after the carrier is replaced with acetylene black (C) and graphite carbon nitride (g-C3N4), the XRD results show that the indium-carbon interstitial composite Pt3InC 0.5 Successfully generated.

[0070] Figure 6 The X-ray powder diffraction analysis patterns of the products prepared in Example 8, Example 9 and Comparative Example 4 of the present invention are as follows; 0.5 Preparation as an example, controlling a single variable, after replacing Pt(acac)2 with H2PtCl6 and N,N-dimethylformamide with PhCH2OH, XRD results show that the carbon interstitial composite Pt3InC 0.5 In addition, in Pt3InC 0.5 After removing the precursor InCl₃ from the Pt / SiO₂ synthesis step, no platinum carbide was found in the Pt / SiO₂. This is because the high atomic mobility of the low-melting-point metal indium (In) facilitates the penetration of heteroatoms into the metal lattice while effectively preventing particle agglomeration, thus ensuring the catalyst's excellent performance and stability.

[0071] Figure 7 The diffuse reflectance Fourier transform infrared spectroscopy (DRIFT) spectra of CH3OH adsorbed on the products prepared in Example 1 and Comparative Example 1 of the present invention; DRIFT analysis showed that Pt3InC 0.5 / SiO2 showed characteristic peaks of *CHOH at 2980, 2972, 2858 and 1034 cm⁻¹, and CH2O* (2923 cm -1 ) and CH3O* adsorbed species (2959, 2846, 2824, 1010 cm -1 ). In contrast, the adsorption intensity of CH3O in Pt3In / SiO2 was significantly enhanced, and no *CHOH intermediate was detected. 0.5 The APR pathway on the Pt3In / SiO2 surface is as follows: CH3OH is continuously dehydrogenated to generate *CH2OH, *CHOH, and finally CO, which then reacts with H2O* to generate CO2 and H2 through WGSR. 0.5 / SiO2 has a stronger CH bond dissociation ability, thereby improving the catalytic activity of methanol liquid phase reforming hydrogen production reaction.

[0072] In order to further verify the catalytic effect of the prepared indium-based-carbon interstitial composite catalyst, the application effect of catalyzing the liquid phase reforming of methanol to produce hydrogen was tested as follows: Application Examples The target products obtained in the examples and comparative examples were applied to methanol liquid phase reforming to produce hydrogen.

[0073] Reaction conditions: The hydrogen production performance of the target sample is systematically evaluated in a high-pressure mechanically stirred microreactor using online gas flow monitoring, gas chromatography analysis and other detection methods.

[0074] The hydrogen production test was carried out with 12 mL of methanol water as the reaction substrate, the reaction pressure was 1 MPa of nitrogen, the reaction temperatures were 140 ℃, 160 ℃, 180 ℃, and 200 ℃, respectively, 5.4 M potassium hydroxide, the stirring rate was 600 r / min, the reaction time was 60 min, and the catalyst addition amount was 10 mg.

[0075] Hydrogen production performance analysis method: An Agilent 8890 gas chromatograph equipped with a pulsed discharge helium ionization detector (PDHID) was used. The chromatographic column was filled with 5Å molecular sieve and had a size of 50 m×0.53 mm×50 μm.

[0076] The analysis conditions were set as: column box temperature 50°C, detector temperature 150°C. This method was used to achieve accurate detection and quantitative analysis of hydrogen production performance.

[0077] Stability test: After the initial performance test, the following steps were performed: the catalytic suspension in the reactor lining was transferred to a centrifuge tube, washed with anhydrous ethanol, and centrifuged at 11,000 rpm for 5 minutes, repeating three times to achieve solid-liquid separation. The recovered catalyst was reloaded into the high-pressure reactor lining. Subsequent cycle tests strictly followed the reaction conditions of the application example (temperature, pressure and other parameters remained consistent) and the performance test process to ensure data comparability. After 10 consecutive cycle tests, Pt3InC 0.5 / The activity retention rate of the SiO2 catalyst (Example 1 and Examples 4-5) reached 93%, showing excellent cyclic stability.

[0078] Under the same reaction conditions, the indium-based-carbon interstitial composites prepared in the examples and comparative examples were applied to methanol liquid phase reforming to produce hydrogen (reaction temperature was 200° C.). Table 1 shows the performance test results of the examples and comparative examples.

[0079] Table 1 Test results of methanol liquid phase reforming hydrogen production using different indium-carbon interstitial composites and traditional alloy compounds

[0080] As can be seen from Table 1, the indium-carbon interstitial composites (Pt3InC 0.5 / SiO2, Pd3InC / SiO2, Ni3InC 0.5 / SiO2), Pt3InC 0.5 / SiO2 has the highest catalytic activity; from Examples 1, 4 and 5, when the loading amount is 0.2 wt.%, the highest relative turnover frequency (TOF) is 31535 h -1 This is because the TOF of a catalytic system essentially reflects the intrinsic catalytic efficiency of the active sites. Low loadings achieve a "few but fine" catalytic conversion by optimizing the dispersion, electronic structure, and mass transfer environment of the active sites, providing a theoretical basis for the design of highly efficient atomically dispersed catalysts.

[0081] In Examples 6, 7, 8, and 9, single-factor variable control experiments were performed, respectively using C or g-C3N4 instead of SiO2 carrier, chloroplatinic acid instead of acetylacetonate platinum metal precursor, and benzyl alcohol instead of DMF solvent for synthesis. The results all successfully prepared indium-carbon interstitial compounds, verifying the universality of this method.

[0082] From the comparison of the results of Comparative Examples 1-3 and Examples 1-3, it is found that in the in-situ deposition reduction technology, when the solvent ethylene glycol (EG) is replaced with N,N-dimethylformamide (DMF) or benzyl alcohol (PhCH2OH), the metal composition of the product changes from the traditional alloy structure (Pt3In, Pd3In and Ni3In) to indium-carbon interstitial composite (Pt3InC 0.5 , Pd3InC and Ni3InC 0.5 ). Through experimental comparison test, Pt3InC 0.5 The C atoms in the Pt3InC are derived from the solvent. The infrared results of CH3OH adsorption show that this performance improvement is mainly due to its significant enhancement of the 0.5 / SiO2's C-H bond dissociation ability. Comparative Example 4 shows that when the InCl3 precursor is eliminated and the indium-carbon interstitial composite is prepared, no platinum carbide phase is detected in the product. This result confirms the key guiding role of indium in the formation of platinum carbide.

[0083] The present invention synthesizes three indium-carbon interstitial composites (Pt3InC 0.5 , Pd3InC and Ni3InC 0.5 ) performance test (as shown in Table 1) to screen out the best performance of a catalyst (Pt3InC 0.5), and then tested different loading amounts. At the optimal loading amount, the performance of the catalyst and its corresponding traditional alloy catalyst (such as Pt3InC 0.5 and Pt3In), and tested Pt3InC 0.5 The stability results are shown in Table 2, which shows the test results of methanol liquid phase reforming hydrogen production at different temperatures for the indium-based-carbon interstitial composite or indium-based composite in the catalysts prepared in Example 5 and Comparative Example 5.

[0084] Table 2 Test results of methanol liquid phase reforming hydrogen production at different temperatures for indium-based-carbon interstitial composites and traditional alloy compounds

[0085] As can be seen from Table 2, from Example 5 and Comparative Example 5, with the same loading amount and SiO2 as the carrier, the indium-based carbon interstitial composite (Pt3InC 0.5 / SiO2) has significantly improved the catalytic hydrogen production activity of 0.2 wt.% Pt3InC / SiO2 compared with the traditional alloy (Pt3In / SiO2) at different temperatures such as 140 ℃, 160 ℃, 180 ℃, and 200 ℃. 0.5 / SiO2 showed remarkable activity for the aqueous phase reforming (APR) of methanol (CH3OH) to produce H2 at 200 ℃, with a turnover frequency of Pt3In / SiO2 (18025 h -1 ) by 1.7 times. This performance improvement is primarily due to the stronger C-H bond dissociation ability of indium-based carbon interstitial compounds compared to traditional alloys, further demonstrating the advantages of the new indium-based carbon interstitial composites. This research may not only provide a simple technique for the controlled synthesis of indium-based carbon interstitial composites, but also encourage fundamental research on indium-based carbon interstitial composites for catalysis and other applications.

[0086] In summary, the research on precious metal-based interstitial compounds aims to solve problems such as the scarcity of precious metal resources and performance bottlenecks. Through in-depth exploration of their structure and properties, it is expected to develop high-performance, low-cost new materials, promote technological progress in multiple fields such as energy, electronics, and chemical industry, and has important scientific significance and application value.

[0087] Of course, the embodiments described above are merely illustrative of the technical solutions of the present invention and do not constitute any limitation on the scope of protection of the present invention. Without departing from the core technical concept and substantial protection scope of the present invention, any equivalent replacement of technical features, adaptive adjustment of technical parameters, optimization and improvement of structural forms, or other derivative technical solutions made by those skilled in the art based on the present invention shall be deemed to fall within the scope of patent protection of the present invention.

Claims

1. An indium-carbon interstitial composite catalyst, characterized in that The indium-carbon interstitial composite material is a carrier and an indium-carbon interstitial composite material supported on the carrier. The chemical structure of the indium-carbon interstitial composite material is M3InC x , wherein M is selected from at least one of Pt, Pd and Ni, and 0.5≤x≤1.

2. The indium-based-carbon interstitial composite catalyst according to claim 1, characterized in that The carrier is selected from at least one of metal oxides, carbon-based carriers, molecular sieve carriers, ceramic carriers, and boron nitride; Preferably, the carrier is selected from at least one of aluminum oxide, silicon oxide, titanium oxide, cerium oxide, zirconium oxide, activated carbon, carbon nanotubes, acetylene black and g-C3N4.

3. The indium-based-carbon interstitial composite catalyst according to claim 1, characterized in that The chemical formula of the indium-carbon interstitial composite is M3InC x , wherein M is selected from one of Pt, Pd and Ni, and x is 0.5 or 1; Or, the loading amount of the indium-carbon interstitial composite is 0.1-3.0 wt%; Preferably, the chemical structural formula of the indium-carbon interstitial composite is Pt3InC 0.5 , Pd3InC and Ni3InC 0.5 .

4. A method for preparing the indium-based-carbon interstitial composite catalyst according to any one of claims 1 to 3, characterized in that: The steps include: The metal precursor, indium chloride and a carrier are added into a solvent and stirred to prepare a mixed solution; the mixed solution is subjected to a hydrothermal reaction, and an indium-based-carbon interstitial composite catalyst is obtained after the reaction is completed.

5. The method for preparing the indium-carbon interstitial composite catalyst according to claim 4, wherein: The molar ratio of the acetylacetonate metal salt to indium chloride is 3:1; Alternatively, the concentration of indium chloride in the solvent is 1.0-1.5 mol / L; Alternatively, the mass ratio of the indium chloride to the carrier is 0.1-3.0 wt%.

6. The method for preparing the indium-carbon interstitial composite catalyst according to claim 4, wherein: The metal precursor is selected from at least one of platinum acetylacetonate, palladium acetylacetonate, nickel acetylacetonate, and chloroplatinic acid; Alternatively, the solvent is selected from at least one of N,N-dimethylformamide and benzyl alcohol.

7. The method for preparing the indium-carbon interstitial composite catalyst according to claim 4, wherein: The stirring speed is 800-1200 r / min, and the stirring time is 5-30 min; Alternatively, the hydrothermal reaction temperature is 180-220°C, the heating rate is 5-15°C / min, and the holding time is 20-30 h; Alternatively, after the reaction is completed, the product is sequentially washed, centrifuged and vacuum dried, and the solvent used for the washing is anhydrous ethanol; The centrifugal speed is 10000-15000 rpm, and the number of centrifugation is 2-5 times; the vacuum drying temperature is 50-65°C, and the drying time is 3-6 hours.

8. Use of the indium-based-carbon interstitial composite catalyst according to any one of claims 1 to 3 in hydrogen fuel cells, hydrogenation reactions and alcohol oxidation reactions; preferably, use in methanol liquid phase reforming hydrogen production reaction.

9. A method for producing hydrogen by liquid phase reforming of methanol, characterized in that: The indium-based-carbon interstitial composite catalyst according to any one of claims 1 to 3 is used.

10. The method for producing hydrogen by liquid phase reforming of methanol according to claim 9, characterized in that: Methanol water is used as the reaction substrate, the reaction atmosphere is nitrogen, the reaction pressure is 0.5-1.5 MPa, the reaction temperature is 140-200 ° C, the reaction time is 30-90 min, and the catalyst addition amount is 8-12 mg.

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