Catalyst for photo-thermal catalytic reaction

Abstract

The invention discloses a catalyst for a photo-thermal catalytic reaction, and belongs to the field of photo-thermal catalysis. The catalyst is a transition metal composite Silicalite-1 zeolite catalyst, and the transition metal composite Silicalite-1 zeolite catalyst is formed by compounding Silicalite-1 zeolite and a transition metal in the VIII group or the IB group or the IIB group in the fourth period. The zeolite molecular sieve is used as a photo-thermal catalyst carrier for the first time, and compared with the prior art, the catalyst is high in catalytic activity, simple to prepare, low in economic and environmental cost, efficient and energy-saving; the product and the catalyst are easy to separate, and post-treatment is simple; the catalyst is easy to reuse and is green and environment-friendly.

Description

Technical Field

[0001] This invention belongs to the field of photothermal catalysis, and specifically relates to a catalyst for photothermal catalytic reactions. Background Technology

[0002] Photothermal catalysis is a highly efficient and green catalytic system that utilizes the entire solar spectrum without requiring additional heat input, through the conversion of photons into heat. Currently, photothermal catalytic materials mainly focus on supported metal oxides, covalent organic frameworks, and semiconductors; metal composite zeolite materials have not been reported in the field of photothermal catalysis.

[0003] Currently, hydrothermal methods are commonly used to synthesize metal-doped zeolite materials, but they suffer from low metal doping levels and poor dispersion. Furthermore, the photothermal catalytic CO2 methanation process is slow due to inherent thermodynamic and kinetic barriers to CO2 activation and multiple proton-coupled electron transfer steps. Consequently, most reported solar-to-chemical (STC) conversion efficiencies of photothermal systems are below 1%, and non-precious metal catalysts exhibit lower activity compared to precious metal catalysts.

[0004] Authorization announcement number CN 113617367 B discloses a noble metal ruthenium single-atom supported catalyst, its preparation method and application. The metal active sites of this invention for photothermal catalytic carbon dioxide conversion mainly rely on noble metals to dissociate H2, further generating hydrogen protons to accelerate the reaction. However, the catalyst preparation cost is high and the activity is still at a low level.

[0005] Authorization announcement number CN 113441159 B discloses a nickel / titanium carbide photothermal catalytic material, its preparation method, and its application. Materials used in photothermal catalytic carbon dioxide conversion typically employ post-loading or post-processing methods, resulting in low metal content and dispersion, poor light absorption performance, and the need for auxiliary heating in the catalytic reaction. Summary of the Invention

[0006] The purpose of this invention is to provide a catalyst for photothermal catalytic reactions. The catalyst is a transition metal composite Silicalite-1 zeolite catalyst. This invention is the first to use zeolite molecular sieves as a photothermal catalyst support. Compared with the prior art, it has high catalytic activity, simple preparation, low economic and environmental costs, and high efficiency and energy saving. The product and catalyst are easy to separate, and the post-processing is simple. The catalyst is easy to reuse and is green and environmentally friendly.

[0007] To address the above issues, the following solutions are provided: A catalyst for photothermal catalytic reactions, wherein the catalyst is a transition metal composite Silicalite-1 zeolite catalyst, wherein the transition metal composite Silicalite-1 zeolite catalyst is a transition metal composite Silicalite-1 zeolite catalyst formed by combining Silicalite-1 zeolite catalyst with a transition metal from Group VIII, Group IB, or Group IIB of Period IV.

[0008] The fourth-period group VIII, IB, or IIB transition metals mentioned are Fe, Co, Ni, Cu, or Zn.

[0009] The Fe, Co, Ni, Cu or Zn are sourced from ferric nitrate nonahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, copper nitrate trihydrate, and zinc nitrate hexahydrate.

[0010] The preparation method of the transition metal composite Silicalite-1 zeolite catalyst: (1) Mix a transition metal source from the fourth period (Group VIII, Group IB, or Group IIB) with a silicon source and add it to an acid solution, then hydrolyze and dry to form a dry gel. (2) Dry and calcine the dry adhesive; (3) Mix the dry adhesive with the template agent and crystallize to obtain a solid product; (4) Remove the template agent and reduce it to obtain the metal composite Silicalite-1 zeolite catalyst.

[0011] The specific steps are as follows: (1) Add the metal source to a mixed solution of water and acid, then add the silicon source, hydrolyze at room temperature for 24 hours, and then heat and stir to form a dry gel; this step is to enable the metal source to form an initial structure with the silicon source.

[0012] (2) Dry the dry glue thoroughly and calcine it in an air atmosphere; this step is crucial for the metal to exist stably in amorphous silica and for the subsequent smooth crystallization of zeolite.

[0013] (3) The dry adhesive is mixed with the template agent and transferred to a hydrothermal reactor for crystallization. The solid product is obtained after washing, drying and grinding. This step is to achieve the smooth crystallization of high-content metal composite Silicalite-1 zeolite.

[0014] (4) The template agent is removed by air calcination, and then reduced to obtain the transition metal composite Silicalite-1 zeolite catalyst. This step is to make the transition metal composite Silicalite-1 zeolite catalyst more stable and to maintain a high degree of metal dispersion.

[0015] The transition metal sources of the fourth period, group VIII, group IB, or group IIB are iron nitrate nonahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, copper nitrate trihydrate, and zinc nitrate hexahydrate.

[0016] In step (1), the molar ratio of silicon dioxide:water:metal source is 1:11.8:0.10-0.16; The preferred molar ratio of silica:water:metal source is 1:11.8:0.12; When the transition metal content is high and uniformly dispersed, the claimed effects of this invention can be achieved; when the transition metal is nickel, with a nickel content of 10%-16% and uniform dispersion, good results can be achieved. When the nickel content is 12%, with Ni-NiO coexisting and uniformly dispersed, the best results can be achieved.

[0017] It exhibits excellent carbon dioxide conversion rate and outstanding solar-to-chemical (STC) energy conversion efficiency when used for photothermal catalytic hydrogenation of carbon dioxide to methane.

[0018] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The optimal nickel-composite Silicalite-1 zeolite catalyst is selected.

[0019] (1) The nickel source and silicon source are mixed and added to an acid solution, and then hydrolyzed and dried to form a dry gel. This step enables the silicon precursor and metal species to co-hydrolyze and condense, preventing the formation of Me-O-Me bonds (Me is a metal).

[0020] (2) Dry and calcine the dry gel; this step enables the metal species to exist stably in amorphous silica and is crucial for the subsequent smooth crystallization of zeolite.

[0021] (3) Mix the dry adhesive with the template agent and crystallize to obtain a solid product; this step yields a metal composite zeolite material with good crystallinity.

[0022] (4) Remove the template agent and reduce it to obtain the nickel composite Silicalite-1 zeolite catalyst; this step makes the metal species exist stably in Silicalite-1 zeolite and maintain a high degree of dispersion.

[0023] This invention provides a method for preparing the nickel-composite Silicalite-1 zeolite catalyst described above, comprising the following steps: In step (1), the nickel source is nickel nitrate hexahydrate; the silicon source is tetraethyl orthosilicate; the acid is hydrochloric acid; and the temperature required for heating and stirring to form dry glue is 80-90 ℃.

[0024] The molar ratio of the final dry adhesive formed in step (1) is silicon dioxide:water:nickel = 1:11.8:0.10-0.16.

[0025] The calcination conditions described in step (2) are 350-550 ℃ for 4-6 hours.

[0026] In step (3), the template agent is tetrapropylammonium hydroxide; the crystallization conditions are 170-190 °C for 3-5 days.

[0027] In step (4), the calcination conditions are 450-600 °C for 4-6 hours; the reduction is carried out in a hydrogen-nitrogen mixed atmosphere; and the reduction conditions are 500-800 °C for 1-4 hours.

[0028] This invention provides an application of the nickel-composite Silicalite-1 zeolite catalyst described above in the photothermal catalytic hydrogenation reaction of carbon dioxide, comprising the following steps: (a) Add nickel-composite Silicalite-1 zeolite catalyst into the glass batch reactor and use a vacuum pump to remove the air from the reactor.

[0029] (b) Introduce carbon dioxide and hydrogen into a glass batch reactor, turn on the light, and carry out the reaction under normal pressure.

[0030] (c) After the reaction, the gaseous products in the reactor are extracted using a micro-syringe and analyzed by a gas chromatograph equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD). The peak areas of the products are then used to calculate the product yield using a standard curve.

[0031] In step (a), the mass of the nickel-composite Silicalite-1 zeolite catalyst is 5-20 mg.

[0032] In step (b), the amounts of carbon dioxide and hydrogen are 20 and 80 mL, respectively.

[0033] In step (b), the light intensity is 1.5-3.5 W / cm². -2 The reaction time is 4-30 min. Beneficial effects

[0034] This invention introduces high-content nickel species (>10%) into zeolite molecular sieves via acid hydrolysis coupled with dry gel conversion crystallization. The nickel species in this target catalyst are highly dispersed, and their strategic combination in S-1 zeolite constructs synergistic Ni-NiO sites.

[0035] The catalyst of this invention has high metal content and dispersion, and the nickel species are in the form of Ni-NiO coexistence, which are responsible for H2 cracking and CO2 activation, respectively. The two work together to promote photothermal catalytic carbon dioxide methanation.

[0036] The catalyst of this invention utilizes the excellent photothermal properties of metal species and the confinement effect of zeolites to ensure the effective activation of CO2 and H2, as well as the stability of the key intermediate *CO, thereby driving highly efficient photothermal catalytic CO2 hydrogenation, achieving a yield of 0.62-23.0 mol g. metal -1 h -1 The optimal CO2 conversion rate and STC were observed. The best catalyst, Ni@S-1, achieved a CO2 conversion rate of 92.7 mol / L under optimal conditions. -2 h -1 (2.7 mol g cat -1 h -1 and 23.0 mol g Ni -1 h -1 This achieved an unprecedented CO2 conversion rate, realizing a significant STC of 9.1%. It pioneered the application of zeolite catalysts in the field of photothermal catalysis.

[0037] This invention successfully introduces high-content, highly dispersed metals into zeolite, achieving highly efficient photothermal conversion and leveraging the heat insulation effect and confinement effect of zeolite on catalytic reaction intermediates. This invention utilizes the advantages of non-precious metal composite zeolite materials, achieving a breakthrough in the field of photothermal catalytic carbon dioxide conversion. This invention exhibits high catalytic activity, achieving unprecedented CO2 conversion rates and significant STC (Self-Conversion Rate). This invention reduces economic costs, the catalyst is easily reusable, and it is environmentally friendly, showing promising application prospects. Attached Figure Description

[0038] Figure 1 The image shows the XRD pattern of Ni@S-1 in Example 1.

[0039] Figure 2 This is the BET plot of Ni@S-1 in Example 1.

[0040] Figure 3 The images shown are (a) SEM and (b) TEM images of Ni@S-1 in Example 1.

[0041] Figure 4 This is the EXAFS diagram of Ni@S-1 in Example 1.

[0042] Figure 5This is the chromatogram of the product from the photothermal catalytic hydrogenation of carbon dioxide using Ni@S-1 in Example 1. The horizontal axis represents the elution time, and the vertical axis represents the elution intensity of methane / carbon monoxide.

[0043] Figure 6 This is an activity graph of Ni@S-1 in Example 1 for the photothermal catalytic hydrogenation of carbon dioxide. The horizontal axis represents the illumination time, and the vertical axis represents the methane / carbon monoxide formation rate and the methane selectivity.

[0044] Figure 7 This is a cycle stability graph of Ni@S-1 in Example 1 for photothermal catalytic carbon dioxide hydrogenation. The horizontal axis represents the number of cycles, and the vertical axis represents the methane / carbon monoxide formation rate and the carbon dioxide conversion rate. Detailed Implementation

[0045] Example 1: Synthesis of a nickel-composite Silicalite-1 zeolite catalyst

[0046] 2.47 g of nickel nitrate hexahydrate was added to a mixed solution of 15 g water and 0.3 g concentrated hydrochloric acid, followed by 15 g of tetraethyl orthosilicate. The mixture was stirred at room temperature for 24 hours. Then, the mixture was stirred at 90 °C to form a dry gel. The molar ratio of the formed dry gel was: SiO2:H2O:Ni = 1:11.8:0.12. The dry gel was further dried thoroughly in a 100 °C oven and then calcined in a muffle furnace at 450 °C for 5 hours.

[0047] Then, 1 g of dry adhesive was mixed evenly with 1.5 g of tetrapropylammonium hydroxide and transferred to a stainless steel hydrothermal reactor with a polytetrafluoroethylene liner for crystallization at 180 °C for 3 days. The solid was separated by filtration, washed with deionized water until neutral, dried at 100 °C overnight, ground into powder, and then calcined at 550 °C for 5 hours in air to remove the template agent. Then, it was reduced at 700 °C for 2 hours in a 10% H2 / 90% N2 atmosphere to obtain the final sample, denoted as 12%Ni@S-1.

[0048] The structural characterization of this catalyst is as follows: Figure 1-4 As shown. Figure 1 XRD analysis showed that the catalyst had good crystallinity and belonged to the MFI topology of Silicalite-1 zeolite. Figure 2 BET indicates that the catalyst has a large specific surface area of ​​389 m². 2 g -1 Micropores and mesopores coexist. Figure 3 SEM images show that the catalyst exhibits a hexagonal prism morphology of approximately 3 μm. Figure 3b TEM showed that the nickel species were in a coexisting state of Ni and NiO, with a size of about 5 nm and uniformly dispersed on Silicalite-1 zeolite. Figure 4 nickel K Near-edge X-ray absorption spectroscopy confirmed the presence of Ni-NiO species in Ni@S-1. Figure 4 b Ni@S-1 nickel K The Fourier transform extended X-ray absorption fine structure spectra of the edges correspond to the Ni-O and Ni-Ni paths at 1.38 Å and 2.15 Å, respectively. Figure 4 The cEXAFS fitting results show the contributions of Ni-O and Ni-Ni.

[0049] The catalyst synthesized by this method directly constructs high-content and highly dispersed Ni-NiO sites in Silicalite-1 zeolite.

[0050] Example 2: Synthesis of an iron-based Silicalite-1 zeolite catalyst

[0051] 3.44 g of ferric nitrate hexahydrate was added to a mixed solution of 15 g water and 0.3 g concentrated hydrochloric acid, followed by 15 g of tetraethyl orthosilicate. The mixture was stirred at room temperature for 24 hours. Then, the mixture was stirred at 90 °C to form a dry gel. The molar ratio of the formed dry gel was: SiO2:H2O:Fe = 1:11.8:0.12. The dry gel was further dried thoroughly in a 100 °C oven and then calcined in a muffle furnace at 450 °C for 5 hours.

[0052] Then, 1 g of dry adhesive was mixed evenly with 1.5 g of tetrapropylammonium hydroxide and transferred to a stainless steel hydrothermal reactor with a polytetrafluoroethylene liner for crystallization at 180 °C for 3 days. The solid was separated by filtration, washed with deionized water until neutral, dried at 100 °C overnight, ground into powder, and then calcined at 550 °C for 5 hours in air to remove the template agent. Then, it was reduced at 700 °C for 2 hours in a 10% H2 / 90% N2 atmosphere to obtain the final sample, denoted as 12%Fe@S-1.

[0053] Example 3: Synthesis of Cobalt Composite Silicalite-1 Zeolite Catalyst

[0054] 2.48 g of cobalt nitrate hexahydrate was added to a mixed solution of 15 g water and 0.3 g concentrated hydrochloric acid, followed by 15 g of tetraethyl orthosilicate. The mixture was stirred at room temperature for 24 hours. Then, the mixture was stirred at 90 °C to form a dry gel. The molar ratio of the formed dry gel was: SiO2:H2O:Co = 1:11.8:0.12. The dry gel was further dried thoroughly in a 100 °C oven and then calcined in a muffle furnace at 450 °C for 5 hours.

[0055] Then, 1 g of dry adhesive was mixed evenly with 1.5 g of tetrapropylammonium hydroxide and transferred to a stainless steel hydrothermal reactor with a polytetrafluoroethylene liner for crystallization at 180 °C for 3 days. The solid was separated by filtration, washed with deionized water until neutral, dried at 100 °C overnight, ground into powder, and then calcined at 550 °C for 5 hours in air to remove the template agent. It was then reduced at 700 °C for 2 hours in a 10% H2 / 90% N2 atmosphere to obtain the final sample, denoted as 12%Co@S-1.

[0056] Example 4: Synthesis of copper-composite Silicalite-1 zeolite catalyst

[0057] 2.06 g of copper nitrate trihydrate was added to a mixed solution of 15 g water and 0.3 g concentrated hydrochloric acid, followed by 15 g of tetraethyl orthosilicate. The mixture was stirred at room temperature for 24 hours. Then, the mixture was stirred at 90 °C to form a dry gel. The molar ratio of the formed dry gel was: SiO2:H2O:Cu = 1:11.8:0.12. The dry gel was further dried thoroughly in a 100 °C oven and then calcined in a muffle furnace at 550 °C for 5 hours.

[0058] Then, 1 g of dry adhesive was mixed with 1.5 g of tetrapropylammonium hydroxide and transferred to a stainless steel hydrothermal reactor with a polytetrafluoroethylene liner for crystallization at 180 °C for 3 days. The solid was separated by filtration, washed with deionized water until neutral, dried at 100 °C overnight, ground into powder, and then calcined at 550 °C for 5 hours in air to remove the template agent. Finally, it was reduced at 700 °C for 2 hours in a 10% H2 / 90% N2 atmosphere to obtain the final sample, denoted as 12% Cu@S-1.

[0059] Example 5: Synthesis of Zinc-Composite Silicalite-1 Zeolite Catalyst

[0060] 2.48 g of zinc nitrate hexahydrate was added to a mixed solution of 15 g water and 0.3 g concentrated hydrochloric acid, followed by 15 g of tetraethyl orthosilicate. The mixture was stirred at room temperature for 24 hours. Then, the mixture was stirred at 90 °C to form a dry gel. The molar ratio of the formed dry gel was: SiO2:H2O:Zn = 1:11.8:0.12. The dry gel was further dried thoroughly in a 100 °C oven and then calcined in a muffle furnace at 550 °C for 5 hours.

[0061] Then, 1 g of dry adhesive was mixed with 1.5 g of tetrapropylammonium hydroxide and transferred to a stainless steel hydrothermal reactor with a polytetrafluoroethylene liner for crystallization at 180 °C for 3 days. The solid was separated by filtration, washed with deionized water until neutral, dried at 100 °C overnight, ground into powder, and then calcined at 550 °C for 5 hours in air to remove the template agent. The sample was then reduced at 700 °C for 2 hours in a 10% H₂ / 90% N₂ atmosphere to obtain the final sample, denoted as 12% Zn@S-1.

[0062] Example 6: The catalysts prepared in Examples 1-5 were used in the photothermal catalytic hydrogenation reaction of carbon dioxide.

[0063] Photothermal catalytic carbon dioxide hydrogenation was carried out under light irradiation. In typical operation, the catalyst (6 mg) was dispersed in water under ultrasonic treatment and then loaded onto a 1.5 cm diameter glass microfiber filter membrane. The sample was dried under vacuum and then placed in a 100 mL glass batch reactor. Subsequently, the reactor was degassed under vacuum and charged with a mixture of CO2 and H2. v / v (1 / 4). The reaction was carried out under 300W xenon lamp illumination. After the reaction, the gaseous products were analyzed using a gas chromatograph equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD).

[0064] Calculation formula: The rate of formation of methane or carbon monoxide (mol g) metal -1 h -1 = Amount of methane or carbon monoxide (mol) / (Mass of catalyst (g) × Mass fraction of metal (wt.%) × Reaction time (s)) Carbon dioxide conversion rate (mol g) Ni -1 h -1 = Rate of methane formation + Rate of carbon monoxide formation Methane selectivity = Amount of methane (mol) / (Amount of methane (mol) + Amount of carbon monoxide (mol)) × 100% Solar energy to chemical energy conversion efficiency (STC) = Output chemical energy / Input solar energy = Molar amount of product × Enthalpy change of reaction (J / mol) / (Solar irradiance (W / m²)) 2 ) × Illuminated area of ​​the reaction system (m²) 2 () × illumination time (s)), where the enthalpy change of the reaction is ∆H CH4 =165 kJ mol -1 ∆H CO =42 kJ mol -1 .

[0065] This catalyst was used in the photothermal catalytic hydrogenation of carbon dioxide. The Ni@S-1 catalyst, with a Ni content of 12 wt.% and reduced at 700 °C, exhibited uniformly dispersed Ni-NiO species. At a catalyst dosage of 6 mg and a light intensity of 3.5 W cm⁻¹, the reaction was successful. -2 CO2 / H2 v : v With a ratio of 1:4 and 4 min of illumination, 92.7 mol m can be achieved. -2 h -1 (2.7 mol g) cat -1 h -1 and 23.0 mol g Ni -1 h -1 The CO2 conversion rate and the best photothermal catalytic activity of STC were observed at 9.1%. Figure 5 The chromatogram of the photothermal catalytic reaction products shows that the products are methane and carbon monoxide, with methane being the main product. Figure 6 This indicates that as the reaction time increases, the product yield gradually increases, and the CH4 selectivity approaches 100%. Figure 7 The results show that the Ni@S-1 catalyst did not show a significant decrease in carbon dioxide conversion rate and product formation rate during ten cycles of testing, indicating that the catalyst has good stability.

[0066] The catalysts prepared in Examples 1-5 were used in the photothermal catalytic hydrogenation of carbon dioxide. The effect of metal type on the photothermal catalytic hydrogenation of carbon dioxide is listed in Table 1 below.

[0067] Table 1. Effects of Silicalite-1 zeolite catalysts with different metal composites on the photothermal catalytic hydrogenation of carbon dioxide. catalyst <![CDATA[CO2 conversion rate (mol g Metal -1 h -1 )]]> <![CDATA[CH4 production rate (mol g Metal -1 h -1 )]]> <![CDATA[CO generation rate (mol g Metal- 1 h -1 )]]> STC (%) 12%Fe@S-1 7.5 3.2 4.3 2.3 12%Co@S-1 3.4 0.9 2.5 0.8 12%Ni@S-1 23.0 15.4 7.6 9.1 12%Cu@S-1 1.8 0.2 1.6 0.3 12%Zn@S-1 0.62 0.02 0.6 0.09 The results show that all five metals possess a certain ability to photothermally catalyze the hydrogenation of carbon dioxide, promoting the reaction, but the product selectivity varies significantly. In particular, the 12% Ni@S-1 catalyst exhibits the highest catalytic activity and methane selectivity, with CO2 conversion rates and CH4 formation rates reaching 23.0 and 15.4 mol g, respectively. Ni -1 h -1 It also achieved an excellent STC of 9.1%.

[0068] The catalyst prepared in Example 1 was used in the photothermal catalytic hydrogenation of carbon dioxide. The effect of nickel content on the photothermal catalytic hydrogenation of carbon dioxide is listed in Table 2 below.

[0069] Table 2. Effect of Silicalite-1 zeolite catalysts with different nickel contents on photothermal catalytic carbon dioxide hydrogenation. catalyst Ni (mol.%) <![CDATA[CO2 conversion rate (mol g Ni -1 h -1 )]]> <![CDATA[CH4 production rate (mol g Ni -1 h -1 )]]> <![CDATA[CO production rate (mol g Ni -1 h -1 )]]> STC (%) 10%Ni@S-1 10 9.6 6.3 3.3 3.8 12%Ni@S-1 12 23.0 15.4 7.6 9.1 14%Ni@S-1 14 14.0 7.5 6.5 4.9 16%Ni@S-1 16 12.5 6.5 6.0 4.3 The results showed that the CO2 conversion rate first increased and then decreased with increasing nickel content. The highest CO2 conversion rate and CH4 formation rate were achieved at a nickel content of 12%, reaching 23.0 and 15.4 mol g, respectively. Ni -1 h -1 It also achieved an excellent STC of 9.1%.

[0070] The catalyst prepared in Example 1 was used in the photothermal catalytic hydrogenation of carbon dioxide. The effect of the catalyst reduction temperature on the photothermal catalytic hydrogenation of carbon dioxide is listed in Table 3 below.

[0071] Table 3. Effect of catalysts at different reduction temperatures on the photothermal catalytic hydrogenation of carbon dioxide. catalyst Reduction temperature (°C) <![CDATA[CO2 conversion rate (mol g Ni -1 h -1 )]]> <![CDATA[CH4 production rate (mol g Ni -1 h -1 )]]> <![CDATA[CO production rate (mol g Ni -1 h -1 )]]> STC (%) Ni@S-1-400 400 8.9 4.3 4.6 2.9 Ni@S-1-500 500 15.6 9.1 6.5 5.6 Ni@S-1-600 600 17.4 12.6 4.8 7.2 Ni@S-1-700 700 23.0 15.4 7.6 9.1 Ni@S-1-800 800 14.8 8.0 6.8 5.2 The results show that a Ni@S-1 catalyst reduced at 700℃ can yield up to 23.0 mol g. Ni The CO2 conversion rate of ⁻¹ h⁻¹ and 15.4 mol g Ni -1 h -1 CH4 generation rate.

Claims

1. A catalyst for photothermal catalytic reactions, characterized in that: The catalyst is a transition metal composite Silicalite-1 zeolite catalyst, which is a transition metal composite Silicalite-1 zeolite catalyst formed by combining Silicalite-1 zeolite with a transition metal from Group VIII, Group IB, or Group IIB of Period IV.

2. The catalyst for photothermal catalytic reactions according to claim 1, characterized in that: The fourth-period group VIII, IB, or IIB transition metals mentioned are Fe, Co, Ni, Cu, or Zn.

3. The catalyst for photothermal catalytic reactions according to claim 2, characterized in that: The Fe, Co, Ni, Cu or Zn are derived from ferric nitrate nonahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, copper nitrate trihydrate, and zinc nitrate hexahydrate.

4. The catalyst for photothermal catalytic reactions according to claim 1, characterized in that: The molar ratio of Group VIII, IB, or IIB transition metals to silicon dioxide in the fourth period is 0.1-0.16:

1.

5. The catalyst for photothermal catalytic reactions according to claim 1 or 2, characterized in that: The preparation method of the transition metal composite Silicalite-1 zeolite catalyst: (1) Mix a transition metal source from the fourth period (Group VIII, Group IB, or Group IIB) with a silicon source and add it to an acid solution, then hydrolyze and dry to form a dry gel. (2) Dry and calcine the dry adhesive; (3) Mix the dry adhesive with the template agent and crystallize to obtain a solid product; (4) Remove the template agent and reduce it to obtain the transition metal composite Silicalite-1 zeolite catalyst.

6. The catalyst for photothermal catalytic reactions according to claim 5, characterized in that: The transition metal sources of the fourth period, group VIII, group IB, or group IIB are iron nitrate nonahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, copper nitrate trihydrate, and zinc nitrate hexahydrate.

7. The catalyst for photothermal catalytic reactions according to claim 5, characterized in that: The fourth-period group VIII, IB, or IIB transition metal is Ni, the silicon source is tetraethyl orthosilicate, and the molar ratio of Ni to SiO2 is 0.1-0.16:1, preferably 0.12:

1.

8. The catalyst for photothermal catalytic reactions according to claim 5, characterized in that: In step (1), the silicon source is tetraethyl orthosilicate; the acid is hydrochloric acid; the drying process requires heating and stirring, and the temperature required to form the dry gel is 80-90 ℃. The molar ratio of the final dry adhesive formed in step (1) is silicon dioxide: water: transition metal of period IV group VIII or IB or IIB is 1:11.8:0.10-0.16; The calcination conditions in step (2) are 350-550 ℃ for 4-6 hours; The template agent in step (3) is tetrapropylammonium hydroxide; the crystallization conditions are 170-190 °C for 3-5 days. In step (4), the template agent is removed by calcination at 450-600 ℃ for 4-6 hours; the reduction is carried out in a hydrogen-nitrogen mixed atmosphere at 500-800 ℃ for 1-4 hours.

9. The catalyst for photothermal catalytic reactions according to any one of claims 1-8, characterized in that: The photothermal catalytic reaction described is the photothermal catalytic reaction of carbon dioxide hydrogenation.

10. The catalyst for photothermal catalytic reactions according to any one of claims 1-8, characterized in that: The photothermal catalytic reaction described is the hydrogenation of carbon dioxide to produce methane and carbon monoxide.

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