A supported noble metal catalyst for reverse water gas shift reaction and a preparation method and application thereof

Abstract

The application provides a supported noble metal catalyst for reverse water gas shift reaction, which comprises a zirconium carbide carrier and an active component uniformly loaded on the carrier; the active component comprises noble metal elements such as Pt, Rh, Au, Ru, Pd and Ir. The application also provides a preparation method of the supported noble metal catalyst, which comprises: preparing an impregnation solution of the active component; mixing the impregnation solution with the carrier; removing the solvent from the mixed solution to obtain a solid product, and grinding the solid product to obtain the supported noble metal catalyst. The supported noble metal catalyst provided by the application has a wide active temperature window (the active temperature interval is 250-500 DEG C), a high CO2 conversion rate (33%-42%) and a high CO selectivity (80%-100%) in the reverse water gas shift reaction; the preparation method is simple, the catalytic effect is remarkable, the catalyst is suitable for the conversion treatment of CO2 in industry, and has a wide popularization and application prospect.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a supported noble metal catalyst and its preparation method, and also to the application of the supported noble metal catalyst in the reverse water-gas shift reaction. Background Technology

[0002] The massive consumption of fossil fuels has led to excessive CO2 emissions, causing major environmental problems such as climate change, global warming, and sea-level rise, posing a serious threat to human daily life. Meanwhile, CO2 is the world's most abundant and cheapest C1 resource, possessing enormous potential for development and utilization. Therefore, improving the efficiency of CO2 capture, storage, and resource utilization is an important direction in current CO2 research. Among the many CO2 treatment and disposal methods, the hydrogenation of CO2 to CO via the reverse water-gas shift reaction (CO2 + H2 = CO + H2O) is a promising research direction. CO is not only an important raw material for Fischer-Tropsch synthesis in industry, but it can also be further hydrogenated into high-value-added chemicals such as olefins and aromatics, and it also has broad application prospects in Mars exploration.

[0003] The current obstacles to the industrial application of reverse water-gas shift reaction lie in overcoming the high energy consumption of C=O bond formation, the generation of byproducts such as CH4, and the tendency of existing catalysts to undergo deactivation behaviors such as agglomeration, oxidation, and carbon deposition under high-temperature conditions, leading to reduced catalytic efficiency. Therefore, the key research focus is on developing highly efficient, highly selective, and highly stable catalysts.

[0004] Catalysts for reverse water-gas shift reactions (RWGS) can be mainly classified into three categories: supported catalysts, oxide catalysts, and carbide catalysts. Among them, supported catalysts possess the dual function of synergistically activating CO2 and dissociating H2, making them the most widely studied and commonly used catalysts in RWGS reactions. Supported catalysts include noble metal catalysts and non-noble metal catalysts. Noble metal catalysts exhibit good catalytic performance and high efficiency, demonstrating extremely high catalytic activity for RWGS reactions. However, some supported noble metal catalysts (such as platinum-based catalysts and rhodium-based catalysts) often cannot simultaneously possess high CO2 conversion rates and high CO selectivity (especially at higher reaction temperatures), which is a problem that urgently needs to be solved in current research on supported noble metal catalysts.

[0005] Commonly used support materials for supported platinum-based catalysts include Al2O3, CeO2, TiO2, Fe2O3, KLTL molecular sieves, and mullite. Yang et al. reported a catalyst using L-type zeolite as a support and Pt as the active component. This catalyst achieved 100% CO selectivity at 400℃, but the CO2 conversion rate was only about 5%. Chinese patent CN106881084A disclosed a catalyst using mullite as a support, Pt as the active component, and one or more of oxides of X (Li, Na, K, Rb, Cs) as promoters. This catalyst could achieve a maximum CO2 conversion rate of ~35%, but the CO selectivity decreased at high temperatures. Chinese patent CN108144637A disclosed a supported platinum-based catalyst using KLTL molecular sieve as a support, Pt as the active component, and introducing alkali metals M (Li, Na, K, Cs) as promoters. This catalyst could achieve a maximum CO2 conversion rate of ~27% and a CO selectivity of nearly 100%, but the preparation method was relatively complex.

[0006] Commonly used support materials for supported rhodium-based catalysts include TiO2, Al2O3, SiO2, zeolite, SrTiO3, and CeO2. Büche et al. investigated the reverse water-gas shift reaction activity of Rh / Al2O3 under H2:CO2 = 4:1 conditions. The results showed that at 400℃, the catalyst achieved a CO2 conversion of 60%, but the CO selectivity was only about 1%. Li et al. prepared a single-atom catalyst Rh1 / ZrO2 by supporting Rh on ZrO2 and investigated its reactivity, finding that it achieved a CO2 conversion of 62% at 440℃, but the CO selectivity was also only 1%.

[0007] Therefore, providing a novel supported noble metal catalyst for reverse water-gas shift reaction to achieve both high CO2 conversion and high CO selectivity during the reverse water-gas shift reaction is a technical problem that urgently needs to be solved. Summary of the Invention

[0008] One of the objectives of this invention is to provide a supported noble metal catalyst that exhibits both high CO2 conversion rate and high CO selectivity in the reverse water-gas shift reaction.

[0009] The second objective of this invention is to provide a method for preparing a supported noble metal catalyst that exhibits both high CO2 conversion rate and high CO selectivity in a reverse water-gas shift reaction.

[0010] The third objective of this invention is to provide an application of a supported noble metal catalyst in a reverse water-gas shift reaction.

[0011] One of the technical solutions adopted to achieve the objective of this invention is: to provide a supported noble metal catalyst for reverse water-gas shift reaction, comprising a support and an active component uniformly supported on the support;

[0012] The support is zirconium carbide; the active component includes one or more of Pt, Rh, Au, Ru, Pd, and Ir; the loading amount of the active component on the support is 0.1 wt.% to 2.0 wt.%.

[0013] In this invention, on the one hand, zirconium carbide is used as the support for the supported noble metal catalyst. Compared with other types of supports, zirconium carbide support can not only efficiently activate and dissociate CO2, but also the generated CO is easily desorbed on zirconium carbide, thereby inhibiting the excessive hydrogenation of CO to form CH4, which significantly improves the selectivity of CO. On the other hand, noble metals are used as active components uniformly loaded on zirconium carbide support, and the active components are more conducive to the activation of H2. The combined effect of the above two aspects enables the supported noble metal catalyst provided by this invention to maintain a high level of CO2 conversion and CO selectivity in the reverse water-gas shift reaction.

[0014] Preferably, the active component is selected from Pt or Rh, and the loading amount of the active component on the support is 0.1 wt.% to 1.5 wt.%. Extensive research has found that using Rh or Pt as the active component in combination with a zirconium carbide support allows the active component to exhibit a higher H2 dissociation capacity. By controlling the loading amount of the active component to no more than 1.5 wt.%, it helps to improve the dispersion of metal atoms, thereby allowing more metal atoms to be exposed on the surface and participate in the reaction, while effectively slowing down the sintering of metal atoms during the reaction process.

[0015] The second objective of this invention is achieved by providing a method for preparing a supported noble metal catalyst for a reverse water-gas shift reaction, comprising the following steps:

[0016] S1. Prepare the impregnation solution for the active components;

[0017] S2. Add the impregnation solution to the carrier and mix thoroughly to obtain a mixed solution;

[0018] S3. Remove the solvent from the mixed solution to obtain a solid product, and grind it to obtain a supported noble metal catalyst for the reverse water-gas shift reaction.

[0019] Further, in step S1, the method for preparing the impregnation solution of the active component includes: dispersing the salt or acid of the active component in a solvent to obtain an impregnation solution with an active component concentration of 1-10 mg / mL. The salt or acid of the active component includes one of the active component's nitrate, chloride, or organic salt.

[0020] Preferably, magnetic stirring is used to promote the full dissolution of the salt or acid of the active component.

[0021] In some preferred embodiments, the active component is Pt, and step S1 uses chloroplatinic acid hexahydrate as a precursor to prepare an impregnation solution for the active component, with water as the solvent.

[0022] In some preferred embodiments, the active component is Rh. In step S1, the impregnation solution of the active component is prepared using rhodium acetylacetonate as a precursor. The ligands in the precursor can be removed by simple heat treatment before use. Furthermore, acetone is used as a solvent, which not only promotes the dissolution of rhodium acetylacetonate but also facilitates the removal of the solvent after the impregnation is completed.

[0023] Furthermore, in step S2, the mixing temperature is 20–30°C, and the mixing time is 6–24 h.

[0024] Preferably, the impregnation solution is added to the carrier in the following manner: the impregnation solution is added to a micro-injection pump, and then the micro-injection pump is used to slowly add the impregnation solution to the solution containing the carrier, so as to make the metal as uniformly dispersed on the surface of the carrier as possible.

[0025] Further, in step S3, the solvent removal method includes either freeze-drying or rotary evaporation drying. The freeze-drying process includes the following steps: cooling at -50°C to -10°C for 6 to 12 hours, followed by vacuuming for 6 to 12 hours, and finally defrosting to room temperature. The rotary evaporation drying process involves drying at a temperature of 30 to 100°C under magnetic stirring conditions.

[0026] Preferably, the solvent is removed by freeze drying, which helps to maintain the original chemical composition and physical properties of the catalyst and is more conducive to the dispersion of the active metal components.

[0027] The third objective of this invention is to provide a supported noble metal catalyst according to one objective of this invention, or the application of a supported noble metal catalyst prepared by the preparation method according to another objective of this invention in a reverse water-gas shift reaction.

[0028] Furthermore, the application includes: first, reducing and activating the supported noble metal catalyst; then applying the reduced and activated supported noble metal catalyst to a fixed-bed reactor to carry out a reverse water-gas shift reaction.

[0029] Preferably, the reduction activation conditions include: the reducing gas is a mixture of H2 and N2, wherein the volume ratio of H2 to N2 in the mixture is 1:9 to 9:1; and the volume hourly space velocity of the reducing gas is 12000 to 60000 h⁻¹.-1 The reduction temperature is 400–600℃, the heating rate is 1–20℃ / min, the pressure is 0.1–1MPa, and the reduction time is 1–4h.

[0030] In this invention, a reduction activation temperature of 400-600°C is used to avoid metal agglomeration caused by excessively high activation temperature, thus ensuring that both CO2 conversion rate and CO selectivity remain at a high level.

[0031] Furthermore, the conditions for the reverse water-gas shift reaction include: the reactant gas is a mixture of H2 and CO2 in a molar ratio of 3:1; and the reactor volume hourly space velocity is 12,000–60,000 h⁻¹. -1 The reaction temperature is 250–500℃, and the reaction pressure is 0.1–1 MPa.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The supported noble metal catalyst for reverse water gas shift reaction provided by the present invention uses zirconium carbide as a support and noble metal as an active component to construct a supported noble metal catalyst for reverse water gas shift reaction. The catalyst has the characteristics of high activity and high selectivity for reverse water gas shift reaction. Its preparation method is simple and it exhibits high CO2 conversion rate and CO selectivity in the reverse water gas shift reaction process.

[0034] (2) The supported noble metal catalyst provided by this invention, when applied to the reverse water-gas shift reaction, exhibits a very wide temperature window, demonstrating good catalytic activity within the temperature range of 250–500℃. It can achieve a maximum CO2 conversion rate of 33–42% while maintaining a maximum CO selectivity of 80%–100%. The preparation process of this supported noble metal catalyst is simple, and its catalytic effect is significant. It is suitable for CO2 conversion in industry and has broad prospects for promotion and application. Attached Figure Description

[0035] Figure 1 The XRD pattern of the catalyst prepared in Example 2 of this invention;

[0036] Figure 2 The CO2 conversion curves of the catalysts prepared in Examples 1-4 and Comparative Example 1 of this invention for the reverse water-gas shift reaction are shown.

[0037] Figure 3 The CO selectivity curves for the reverse water-gas shift reaction of the catalysts prepared in Examples 1-4 and Comparative Example 1 of this invention are shown.

[0038] Figure 4The CO2 conversion curves for the reverse water-gas shift reaction of the catalysts prepared in Examples 5 and 6 of this invention and Comparative Examples 2-5 are shown.

[0039] Figure 5 CO selectivity curves for the reverse water-gas shift reaction of the catalysts prepared in Examples 5 and 6 of this invention and Comparative Examples 2-5;

[0040] Figure 6 The CO yield curves for the reverse water-gas shift reaction of the catalysts prepared in Examples 5 and 6 of this invention and Comparative Examples 2-5 are shown.

[0041] Figure 7 The CO2 conversion curves for the reverse water-gas shift reaction of the catalysts prepared in Example 2 and Comparative Examples 6-8 of this invention are shown.

[0042] Figure 8 The CO selectivity curves for the reverse water-gas shift reaction of the catalysts prepared in Example 2 and Comparative Examples 6-8 of this invention are shown.

[0043] Figure 9 The CO yield curves are for the reverse water-gas shift reaction of the catalysts prepared in Example 2 and Comparative Examples 6-8 of this invention. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0046] This invention provides a supported noble metal catalyst for a reverse water-gas shift reaction, comprising a support and an active component uniformly supported on the support; the support is zirconium carbide; the active component comprises one or more of Pt, Rh, Au, Ru, Pd, and Ir; the loading amount of the active component on the support is 0.1 wt.% to 2.0 wt.%.

[0047] The method for preparing the supported noble metal catalyst for reverse water-gas shift reaction provided by the present invention includes the following steps:

[0048] Step 1: Disperse the salt or acid of the active component in a solvent to obtain an impregnation solution with an active component concentration of 1-10 mg / mL. The salt or acid of the active component includes one of the active component's nitrate, chloride, or organic salt. Magnetic stirring is used to promote the complete dissolution of the active component's salt or acid.

[0049] Step 2: Add the impregnation solution to a micro-injection pump, and then use the micro-injection pump to slowly add the impregnation solution to the carrier, so that the metal is evenly dispersed on the surface of the carrier as much as possible. Mix thoroughly at 20-30°C for 6-24 hours to obtain a mixed solution.

[0050] Step 3: Remove the solvent from the mixed solution by freeze-drying or rotary evaporation to obtain a solid product. Freeze-drying includes the following steps: cooling at -50℃ to -10℃ for 6 to 12 hours, followed by vacuuming for 6 to 12 hours, and finally defrosting to room temperature; rotary evaporation is carried out at 30 to 100℃ with stirring using a magnetic stirrer. The resulting solid product is ground to obtain a supported noble metal catalyst for the reverse water-gas shift reaction.

[0051] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0052] The main parameters involved in the various embodiments and comparative examples of the present invention are shown in Table 1 below:

[0053] Table 1

[0054]

[0055] Example 1

[0056] Weigh 200 mg of zirconium carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 1 mL of the above chloroplatinic acid solution to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.2% Pt / ZrC catalyst.

[0057] Example 2

[0058] Weigh 200 mg of zirconium carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 2 mL of the above chloroplatinic acid solution to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.4% Pt / ZrC catalyst.

[0059] Example 3

[0060] Weigh 200 mg of zirconium carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 4 mL of the above chloroplatinic acid solution to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.8% Pt / ZrC catalyst.

[0061] Example 4

[0062] Weigh 200 mg of zirconium carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 7.5 mL of the above chloroplatinic acid solution to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 1.5% Pt / ZrC catalyst.

[0063] Example 5

[0064] Weigh 200 mg of zirconium carbide; weigh 3.27 mg of rhodium triacetylacetonate (97%) and dissolve it in 4 mL of acetone, stirring thoroughly to obtain a rhodium triacetylacetonate solution with a concentration of 0.82 mg / mL; add 1 mL of the above solution to zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; evaporate the thoroughly stirred mixture to dryness at room temperature by rotary evaporation, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.1% Rh / ZrC catalyst.

[0065] Example 6

[0066] Weigh 200 mg of zirconium carbide; weigh 3.27 mg of rhodium triacetylacetonate (97%) and dissolve it in 4 mL of acetone, stirring thoroughly to obtain a rhodium triacetylacetonate solution with a concentration of 0.82 mg / mL; add 4 mL of the above solution to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; evaporate the thoroughly stirred mixture to dryness at room temperature by rotary evaporation, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.4% Rh / ZrC catalyst.

[0067] Comparative Example 1

[0068] Weigh 200 mg of zirconium carbide; add 2 mL of deionized water to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the ZrC catalyst.

[0069] Comparative Example 2

[0070] Weigh 200 mg of zirconium carbide; add 4 mL of acetone to the zirconium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; evaporate the thoroughly stirred mixture to dryness at room temperature by rotary evaporation, and grind the resulting powdered solid thoroughly. The obtained sample is the ZrC catalyst H.

[0071] Comparative Example 3

[0072] Weigh 200 mg of monoclinic zirconium dioxide; weigh 3.27 mg of rhodium triacetylacetonate (97%) and dissolve it in 4 mL of acetone, stirring thoroughly to obtain a rhodium triacetylacetonate solution with a concentration of 0.82 mg / mL; add 1 mL of the above solution to the zirconium dioxide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; evaporate the thoroughly stirred mixture to dryness at room temperature by rotary evaporation, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.1% Rh / m-ZrO2 catalyst.

[0073] Comparative Example 4

[0074] Weigh 200 mg of monoclinic zirconium dioxide; weigh 3.27 mg of rhodium triacetylacetonate (97%) and dissolve it in 4 mL of acetone, stirring thoroughly to obtain a rhodium triacetylacetonate solution with a concentration of 0.82 mg / mL; add 4 mL of the above solution to the zirconium dioxide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; evaporate the thoroughly stirred mixture to dryness at room temperature by rotary evaporation, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.4% Rh / m-ZrO2 catalyst.

[0075] Comparative Example 5

[0076] Weigh 200 mg of monoclinic zirconium dioxide; add 4 mL of acetone to the zirconium dioxide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; evaporate the thoroughly stirred mixture to dryness at room temperature by rotary evaporation, and grind the resulting powdered solid thoroughly. The obtained sample is the m-ZrO2 catalyst.

[0077] Comparative Example 6

[0078] Weigh 200 mg of titanium carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 2 mL of the above chloroplatinic acid solution to the titanium carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.4% Pt / TiC catalyst.

[0079] Comparative Example 7

[0080] Weigh 200 mg of tungsten carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 2 mL of the above chloroplatinic acid solution to titanium nitride. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.4% Pt / WC catalyst.

[0081] Comparative Example 8

[0082] Weigh 200 mg of silicon carbide; weigh 12.6 mg of chloroplatinic acid hexahydrate and dissolve it in 12 mL of deionized water, stirring thoroughly to obtain a chloroplatinic acid solution with a concentration of 1.05 mg / mL; add 2 mL of the above chloroplatinic acid solution to the silicon carbide. Place the resulting mixture on a magnetic stirrer and stir for 8 hours until homogeneous; freeze-dry the thoroughly stirred mixture using a freeze dryer, and grind the resulting powdered solid thoroughly. The obtained sample is the 0.4% Pt / SiC catalyst.

[0083] Performance testing

[0084] The catalysts prepared in Examples 1-6 and Comparative Examples 1-8 were subjected to reverse water-gas shift reaction performance tests. The catalyst activity was expressed as CO2 conversion rate and CO selectivity, and the concentrations of CO2, CO and CH4 were detected and analyzed using a chromatograph.

[0085] In this invention, the activity of the catalyst for the reverse water-gas shift reaction is evaluated by the following indicators: CO2 conversion rate, CO selectivity, and CO yield:

[0086]

[0087]

[0088] Yield(Co%)=Conversion(Co2%)×Selectivity(CO%).

[0089] The specific test conditions are as follows: The performance test of the reverse water-gas shift reaction was conducted in a fixed-bed quartz tube reactor. The catalyst loading was 100 mg. First, it was reduced and activated for 2 hours in a 10% H2 / N2 mixed gas atmosphere at 500℃ and a flow rate of 40 mL / min. The heating rate was 10℃ / min, and the pressure was 0.1 MPa. Then, without removing the reduced and activated catalyst, the test was conducted at a reaction temperature of 250℃~500℃, with a reaction temperature interval of 50℃. The concentration of CO2 in the feed gas was 0.24 mol / mol, the concentration of H2 (reducing gas) was 0.72 mol / mol, the concentration of N2 (equilibrium gas) was 0.04 mol / mol, the total reaction gas flow rate was 40 mL / min, and the pressure was 0.1 MPa. The reactor was a quartz tube with an inner diameter of 7 mm, and the real-time reaction temperature environment was provided by a vertical tubular heater with a temperature control system. The test results are as follows: Figure 2-9 As shown.

[0090] Figure 1 The XRD pattern of the 0.4% Pt / ZrC catalyst prepared in Example 2 after the above reduction and activation steps is shown in the spectrum. Analysis of the spectrum shows that the Pt element in the catalyst prepared in Example 2 is uniformly dispersed on the support, and the structure of the support has not changed after high-temperature reduction and activation.

[0091] Depend on Figure 2-3 It can be seen that in the test temperature range of 250℃~500℃, the Pt / ZrC catalyst in Examples 1-4 can achieve a CO2 conversion rate of up to ~42% while maintaining a CO selectivity of up to 99%~100%. Compared with the support, the catalytic performance is greatly improved, and it overcomes the defect that the supported platinum-based catalyst is difficult to maintain a high CO2 conversion rate and CO selectivity in the reverse water-gas shift reaction at high temperature.

[0092] Depend on Figure 4-6 It can be seen that, in Examples 5 and 6, within the test temperature range of 250℃ to 500℃, the Rh / ZrC catalyst achieved a CO2 conversion rate of up to ~33%, while maintaining a CO selectivity of ~80% to 95%. This represents a significant improvement in catalytic performance compared to the supported catalyst. Furthermore, compared to Rh / m-ZrO2 prepared using the commonly used support m-ZrO2, the CO selectivity of Rh / ZrC is several times higher. Figure 6As shown, the final CO yield was nearly 30% higher than the former, thus optimizing the low CO selectivity and CO yield defects of the supported rhodium-based catalyst in the catalytic reverse water-gas shift reaction. This demonstrates that the catalyst prepared by this invention using zirconium carbide as a support and combined with the active component metallic rhodium has excellent performance.

[0093] Depend on Figure 7-9 It can be seen that, compared with the catalysts prepared by Comparative Examples 6-8 using titanium carbide, silicon carbide and tungsten carbide as supports and platinum as the active component, under the same platinum loading conditions, the catalyst prepared by Example 2 using zirconium carbide as a support showed higher CO2 conversion and CO yield. Moreover, the higher the temperature, the more obvious its advantage became, which proved that the catalyst prepared by the present invention using zirconium carbide as a support and platinum as the active component has excellent performance.

[0094] Furthermore, the catalytic performance of the supported noble metal catalysts prepared in Examples 1-6 at temperatures above 400°C is shown in Table 2 below.

[0095] Table 2

[0096]

[0097] As shown in the table above, the catalyst prepared by supporting platinum metal as an active component with zirconium carbide exhibits excellent CO2 conversion performance at high temperatures, with a CO2 conversion rate of 21% to 42% while maintaining a CO selectivity of over 99%, overcoming the shortcomings of previous platinum-based catalysts that could not maintain both high conversion rate and high selectivity at high temperatures. The catalyst with rhodium metal as an active component supported by zirconium carbide has a slightly lower CO2 conversion rate at high temperatures than the former, but it maintains a CO selectivity of 80% to 94%, overcoming the shortcomings of traditional rhodium-based catalysts that tend to generate methane.

[0098] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. The application of a supported noble metal catalyst in a reverse water-gas shift reaction, characterized in that, The supported noble metal catalyst comprises a support and an active component uniformly supported on the support; the support is zirconium carbide; the active component is selected from Pt or Rh; the loading amount of the active component on the support is 0.1 wt.%~2.0 wt.%. The conditions for the reverse water-gas shift reaction include: the reactant gas is a mixture of H2 and CO2 in a molar ratio of 3:1; and the reactor volume hourly space velocity is 12,000 to 60,000 h⁻¹. -1 The reaction temperature is 250~500℃, and the reaction pressure is 0.1~1MPa.

2. The application according to claim 1, characterized in that, The preparation method of the supported noble metal catalyst includes the following steps: S1. Prepare the impregnation solution for the active components; S2. Add the impregnation solution to the carrier and mix thoroughly to obtain a mixed solution; S3. Remove the solvent from the mixed solution to obtain a solid product, and grind it to obtain a supported noble metal catalyst for the reverse water-gas shift reaction.

3. The application according to claim 2, characterized in that, In step S1, the method for preparing the impregnation solution of the active component includes: dispersing the salt or acid of the active component in a solvent to obtain an impregnation solution with an active component concentration of 1~10 mg / mL.

4. The application according to claim 3, characterized in that, The salt or acid of the active component includes one of the following: nitrate, chloride, or organic salt of an active metal.

5. The application according to claim 2, characterized in that, In step S2, the mixing temperature is 20~30℃ and the mixing time is 6~24h.

6. The application according to claim 2, characterized in that, In step S3, the solvent removal method includes either freeze drying or rotary evaporation drying.

7. The application according to claim 1, characterized in that, First, the supported noble metal catalyst is reduced and activated; then, the reduced and activated supported noble metal catalyst is applied to a fixed-bed reactor to carry out a reverse water-gas shift reaction.

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