Preparation method of plasmonic photocatalyst for carbon dioxide reduction to produce methane with full spectrum response

Abstract

The application discloses a preparation method of a full-spectrum response carbon dioxide reduction methane plasmonic photocatalyst, and belongs to the technical field of photocatalytic reduction of CO2.The plasmonic W 18 O 49 nanowire photocatalyst is prepared by using the preparation method of the full-spectrum response CO2 reduction CH4 plasmonic photocatalyst with the above structure, and the prepared Au, Ag or Ni metal ion doped plasmonic W 18 O 49 nanowire has strong ultraviolet-visible-near infrared light absorption capacity and rich surface oxygen vacancy concentration, is beneficial to adsorption and activation of CO2 molecules, meanwhile, the catalyst surface can effectively stabilize the CO intermediate generated in the process of photocatalytic reduction of CO2, and remarkably improves the performance and selectivity of the original plasmonic W * O 18 in the process of photocatalytic reduction of CO2. 49 ​

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of photocatalytic reduction of CO2, in particular to a preparation method of a full-spectrum-response plasmonic photocatalyst for reduction of carbon dioxide to prepare methane. BACKGROUND

[0002] With the acceleration of industrialization, the dependence and consumption of fossil energy by human beings continue to rise, which leads to a sharp rise in the concentration of CO2 in the atmosphere, thereby intensifying global warming and climate change. As a major greenhouse gas, the emission reduction and resource utilization of CO2 have become a hot issue of global concern.

[0003] Among the numerous CO2 resource utilization technologies, the photocatalytic CO2 reduction technology uses solar energy as a driving energy source and does not require additional power input, which is a completely green energy conversion mode. In addition, photocatalytic CO2 reduction is usually carried out at room temperature and pressure, without harsh reaction conditions, thereby reducing energy consumption and equipment requirements. The photocatalytic CO2 reduction technology not only can reduce the emission of greenhouse gases, but also can convert CO2 into high-value fuels (such as CH4), thereby alleviating the current energy shortage problem. However, due to the high CO2 activation energy barrier and the multi-step proton-coupled electron transfer process, the realization of photocatalytic CO2 directional reduction to prepare CH4 still faces some challenges.

[0004] At present, non-metal plasmonic W 18 O 49 Semiconductor materials have been proved to be effective in photocatalytic reduction of CO2 to prepare fuels due to their full-spectrum absorption characteristics, rich surface oxygen vacancies and rich surface plasmonic hot carriers. However, due to the lack of stable active sites for CO intermediates on the surface of the semiconductor materials, the performance and selectivity of the semiconductor materials in photocatalytic CO2 reduction to prepare CH4 are still insufficient, and it is urgent to construct active sites on the surface of the catalysts to enhance the performance and selectivity of the catalysts in photocatalytic CO2 reduction to prepare CH4. * CO intermediates, the selectivity of the semiconductor materials in photocatalytic CO2 reduction can be controlled, and CH4 can be prepared with high efficiency and high selectivity. SUMMARY

[0005] The application aims to provide a preparation method of a full-spectrum-response plasmonic photocatalyst for reduction of carbon dioxide to prepare methane, which can enhance the stability of adsorption of CO intermediates, control the selectivity of the photocatalyst in photocatalytic CO2 reduction, and realize the preparation of CH4 with high efficiency and high selectivity. * CO intermediates, the selectivity of the semiconductor materials in photocatalytic CO2 reduction can be controlled, and CH4 can be prepared with high efficiency and high selectivity.

[0006] To achieve the above-mentioned purpose, the first aspect of the application provides a preparation method of a full-spectrum-response plasmonic photocatalyst for reduction of carbon dioxide to prepare methane, in which tungsten hexacarbonyl and a doped metal salt are dissolved in anhydrous ethanol, and a metal ion-doped plasmonic W 18 O 49The nanowire photocatalyst; the doped metal salt is selected from at least one of silver nitrate, nickel chloride or chloroauric acid.

[0007] Preferably, in the preparation method of the above-mentioned full-spectrum response carbon dioxide reduction to prepare methane plasmonic photocatalyst, the purity of the tungsten hexacarbonyl, silver nitrate, nickel chloride, chloroauric acid is greater than 99%; the concentration of the tungsten hexacarbonyl in anhydrous ethanol is 5-10 mg / mL.

[0008] Preferably, in the preparation method of the above-mentioned full-spectrum response carbon dioxide reduction to prepare methane plasmonic photocatalyst, the mass percentage of the metal ion in the doped metal salt and the final product W 18 O 49 is 0.15% to 1.4%.

[0009] Preferably, in the preparation method of the above-mentioned full-spectrum response carbon dioxide reduction to prepare methane plasmonic photocatalyst, the temperature of the solvothermal reaction is 160-190 DEG C, and the hydrothermal time is 12-24 hours.

[0010] The second aspect of the present application provides a metal ion doped plasmonic W 18 O 49 photocatalyst obtained by the above preparation method.

[0011] The third aspect of the present application provides an application of the prepared metal ion doped plasmonic W 18 O 49 photocatalyst in photocatalytic CO2 reduction to prepare CH4.

[0012] Preferably, the specific method of the application of the plasmonic W 18 O 49 photocatalyst in photocatalytic CO2 reduction to prepare CH4 is as follows: dispersing the metal ion doped non-metal plasmonic W 18 O 49 photocatalyst in deionized water, coating the dispersed suspension on a glass sheet and drying under infrared lamp irradiation, then placing the glass sheet in a photocatalytic reactor and sealing with a thick quartz cover; purging the entire reactor with high-purity nitrogen to exclude air, filling high-purity CO2 gas into the reactor before the reaction, and adding a small amount of deionized water at the bottom of the reactor; using a xenon lamp as a simulated sunlight to carry out CO2 reduction experiment.

[0013] Preferably, in the application of the plasmonic W 18 O 49 photocatalyst in photocatalytic CO2 reduction to prepare CH4, the amount of the photocatalyst is 5 mg, the amount of the deionized water is 0.4 mL, and the area of the glass sheet is 9.61 cm 2 .

[0014] Preferably, in the above plasmonic W 18 O 49 In the application of the photocatalyst in the photocatalytic CO2 reduction to prepare CH4, the volume of the photocatalytic reactor is 180 mL, the power of the infrared lamp is 150 W, and the drying time is 10 minutes; the wavelength range of the xenon lamp simulating sunlight is 200-1100 nm, and the light intensity is 150-300 mW / cm 2 More preferably, the light intensity is 200 mW / cm 2 .

[0015] Preferably, in the above plasmonic W 18 O 49 In the application of the photocatalyst in the photocatalytic CO2 reduction to prepare CH4, the purging time of the high-purity nitrogen is 20 min, the filling time of the high-purity CO2 is 20 min, and the amount of the deionized water added to the bottom of the reactor is 0.2 mL.

[0016] Therefore, the application adopts the above structure to prepare a full-spectrum response carbon dioxide reduction to prepare methane plasmonic photocatalyst, and uses tungsten hexacarbonyl, silver nitrate, nickel chloride or chloroauric acid as raw materials, and a solvent thermal reaction in an ethanol solution is performed to prepare a non-metal plasmonic W 18 O 49 Nanowire photocatalyst. The prepared metal ion doped non-metal plasmonic W 18 O 49 Nanowire has full-spectrum absorption of ultraviolet-visible-near infrared, which is superior to most reported semiconductor photocatalytic materials; the surface of the photocatalyst has abundant oxygen vacancies, which is beneficial to the adsorption and activation of CO2 molecules, and the high-energy hot electrons and holes generated by the surface plasmon resonance effect are beneficial to the photocatalytic CO2 reduction reaction; the doping of Au, Ag or Ni metal ions can effectively stabilize the CO intermediate in the photocatalytic CO2 reduction process, and regulate the photocatalytic CO2 reduction selectivity of the non-metal plasmonic W * O 18 Nanowire, and improve the yield and selectivity of CH4. The photocatalytic CO2 reduction process only uses H2O as an electron donor, avoids the waste of organic sacrificial agents, and does not pollute the environment. In addition, the catalyst preparation method of the application is simple, the research content involved conforms to the current concept of sustainable development, and has potential application prospect. 49

[0017] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0018] ​Figure 1 X-ray diffraction patterns of the synthesized W 18 O 49 W doped with Au, Ag and Ni metal ions 18 O 49 X-ray diffraction patterns of the synthesized W

[0019] Figure 2 X-ray diffraction patterns of the synthesized W 18 O 49 W doped with Au, Ag and Ni metal ions 18 O 49 UV-Vis-NIR diffuse reflectance spectra of the synthesized W

[0020] Figure 3 X-ray diffraction patterns of the synthesized W 18 O 49 W doped with Au, Ag and Ni metal ions 18 O 49 Transmission electron microscopy images of the synthesized W

[0021] Figure 4 Device structure diagram for photocatalytic CO2 reduction reaction

[0022] Figure 5 CH4 production over time during photocatalytic CO2 reduction of the synthesized sample

[0023] Figure 6 CO production over time during photocatalytic CO2 reduction of the synthesized sample

[0024] Figure 7 CH4 and CO yields and CH4 production selectivity during photocatalytic CO2 reduction of the synthesized sample DETAILED DESCRIPTION

[0025] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the description of the drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0026] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Multiple" generally includes at least two.

[0027] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0028] The first aspect of the present invention provides a method for preparing a plasmonic photocatalyst for carbon dioxide reduction to methane with a full spectrum response, wherein tungsten hexacarbonyl and a doped metal salt are dissolved in anhydrous ethanol, and a metal ion-doped plasmonic W is prepared by a solvent thermal reaction. 18 O 49 Nanowire photocatalyst; the doped metal salt is selected from at least one of silver nitrate, nickel chloride or chloroauric acid.

[0029] To further optimize the above technical solution, the purity of the tungsten hexacarbonyl, silver nitrate, nickel chloride, and chloroauric acid is greater than 99%; the concentration of tungsten hexacarbonyl in anhydrous ethanol is 5-10 mg / mL.

[0030] In order to further optimize the above technical solution, the metal ions in the doped metal salt are mixed with the final product W 18 O 49 The mass percentage is 0.15% to 1.4%.

[0031] To further optimize the above technical solution, the temperature of the solvent thermal reaction is 160-190°C and the hydrothermal time is 12-24 hours.

[0032] The second aspect of the present invention provides a metal ion doped plasmon W obtained by the above preparation method. 18 O 49 photocatalyst.

[0033] The third aspect of the present invention provides a prepared metal ion-doped plasmon W 18 O 49 Application of photocatalysts in photocatalytic reduction of CO2 to produce CH4.

[0034] In order to further optimize the above technical solution, plasmon W 18 O 49 The specific method of photocatalyst in photocatalytic CO2 reduction to produce CH4 is: metal ion doped non-metal plasmon W 18 O 49The photocatalyst is dispersed in deionized water, the dispersed suspension is coated on a glass sheet and dried under infrared lamp irradiation, then the glass sheet is placed in a photocatalytic reactor and sealed with a thick quartz cover; the entire reactor is purged with high-purity nitrogen to exclude air, before the reaction, high-purity CO2 gas is filled into the reactor, and a small amount of deionized water is added at the bottom of the reactor; a xenon lamp is used as simulated sunlight to carry out the CO2 reduction experiment.

[0035] To further optimize the above technical solution, the amount of photocatalyst is 5 mg, the amount of deionized water is 0.4 mL, the area of the glass sheet is 9.61 cm 2 .

[0036] To further optimize the above technical solution, the volume of the photocatalytic reactor is 180 mL, the power of the infrared lamp is 150 W, and the drying time is 10 minutes; the wavelength range of the xenon lamp simulated sunlight is 200-1100 nm, and the light intensity is 150-300 mW / cm 2 , more preferably, the light intensity is 200 mW / cm 2 .

[0037] To further optimize the above technical solution, the purging time of high-purity nitrogen is 20 min, the filling time of high-purity CO2 is 20 min, and the amount of deionized water added at the bottom of the reactor is 0.2 mL.

[0038] In order to more clearly and detailedly introduce the preparation method of the full-spectrum response carbon dioxide reduction methane plasmonic photocatalyst provided by the embodiment of the application, the following will be described in combination with specific embodiments.

[0039] Example 1

[0040] Full-spectrum response plasmonic W 18 O 49 Preparation of nanowires

[0041] 180 mg tungsten hexacarbonyl powder is fully dissolved in 30 mL anhydrous ethanol under vigorous stirring, stirring is continued for 10 minutes, then the precursor solution is transferred to a 50 mL volume polytetrafluoroethylene-lined stainless steel autoclave, and solvent thermal reaction is carried out at 180℃ for 24 hours. After the reaction is completed, the synthesized plasmonic W 18 O 49 catalyst is centrifuged out, washed with ethanol for several times, and dried in an oven at 65℃ for 2.5 hours, to obtain plasmonic W 18 O 49 nanowires.

[0042] Example 2

[0043] Au, Ag or Ni ion-doped plasmonic W with full spectrum response 18 O 49 Preparation of nanowires

[0044] 180 mg of tungsten hexacarbonyl powder was fully dissolved in 25 mL of anhydrous ethanol under vigorous stirring. 1.248 mg of chloroauric acid (or 0.571 mg of silver nitrate, or 0.899 mg of nickel chloride) was dissolved in 5 mL of anhydrous ethanol. The two were mixed evenly and stirred for 10 minutes. The precursor solution was then transferred to a 50 mL polytetrafluoroethylene-lined stainless steel autoclave and subjected to solvent thermal reaction at 180 ° C for 24 hours. After the reaction was completed, it was cooled to room temperature and the synthesized plasmon W was 18 O 49 The catalyst was centrifuged, washed with ethanol several times, and dried in an oven at 65°C for 2.5 hours to obtain Au, Ag, or Ni ion-doped plasmon W. 18 O 49 Nanowires (named Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 or Ni 0.35 -W 18 O 49 ).

[0045] The synthesized plasmon W 18 O 49 Nanowires or plasmon W doped with Au, Ag, and Ni ions 18 O 49 The nanowires were subjected to X-ray diffraction analysis. Figure 1 As shown, the synthesized plasmon W 18 O 49 and plasmonic W doped with Au, Ag, and Ni ions 18 O 49 Has good crystallinity, corresponding to W 18 O 49 The standard diffraction pattern of W is JCPDS:71-2450. The diffraction peak at around 23° corresponds to W 18 O 49 The (010) crystal plane of Au, Ag and Ni metal ions doping will reduce the diffraction intensity of the (010) crystal plane, indicating that Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 or Ni 0.35 -W 18 O49 The crystallinity of the sample slightly decreased. The metal element-doped W 18 O 49 The lattice structure of the sample was basically consistent with that of the original W 18 O 49 , but the (010) crystal plane slightly shifted to a high angle, which was caused by the change of the lattice constant of W 18 O 49 due to the metal element doping.

[0046] The synthesized plasmonic W 18 O 49 nanowires or Au, Ag and Ni ion-doped plasmonic W 18 O 49 nanowires were subjected to ultraviolet-visible-near infrared diffuse reflectance spectroscopy analysis. As shown in Figure 2 , the prepared W 18 O 49 , Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 and Ni 0.35 -W 18 O 49 samples all exhibited surface plasmon resonance absorption peaks in addition to the intrinsic semiconductor absorption, showing ultraviolet-visible-near infrared full spectrum absorption characteristics. However, the light absorption of the Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 and Ni 0.35 -W 18 O 49 samples slightly decreased, which might be caused by the decrease of the crystallinity.

[0047] The synthesized plasmonic W 18 O 49 nanowires or Au, Ag and Ni ion-doped plasmonic W 18 O 49 nanowires were subjected to transmission electron microscopy characterization. As shown in Figure 3 , the prepared plasmonic W 18 O 49 or Au, Ag and Ni ion-doped plasmonic W 18 O 49 all exhibited nanowire morphology, indicating that the metal ion doping did not affect the morphology of W 18 O 49The morphology of the nanowires has little effect on the photocatalytic activity. The diameter of the nanowires is about 8-15 nm and the length is about 0.2-1 μm.

[0048] Example 3

[0049] Plasmonic W 18 O 49 , Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 and Ni 0.35 -W 18 O 49 Application of the sample in photocatalytic reduction of CO2

[0050] As shown in Figure 4 , a cylindrical reactor with a volume of 180 mL and a quartz top cover at the top was used as the reaction device for photocatalytic reduction of CO2, and the reaction temperature was controlled at 25°C by the inlet and outlet of the circulating cooling water of the reactor, the top was the direction of light irradiation, and the catalyst was placed at the bottom of the reactor.

[0051] 5 mg of plasmonic W 18 O 49 , Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 or Ni 0.35 -W 18 O 49 photocatalyst was weighed, 0.4 mL of deionized water was added, and a uniform catalyst dispersion was obtained by ultrasonic dispersion treatment for 5 minutes. The catalyst dispersion was uniformly drop-coated on a circular glass sheet with an area of 9.61 cm 2 , and dried under the irradiation of an infrared lamp with a power of 150 W for 10 minutes to obtain a uniform photocatalyst-coated film. The photocatalyst-coated film was placed at the bottom of the reactor and covered with a quartz top cover. The reactor was purged with high-purity nitrogen for 20 minutes to remove air, and then high-purity CO2 was used to fill the reactor for 20 minutes as the reactant, while 0.2 mL of deionized water was added at the bottom of the reactor as the proton source. A 300 W xenon lamp was used as the simulated sunlight light source with a wavelength range of 200-1100 nm and an irradiation intensity of 200 mW / cm 2 . The photocatalytic CO2 reduction experiment was carried out by top irradiation, and the reaction products were detected and analyzed by gas chromatography every half hour.

[0052] The measured photocatalytic CO2 reduction product carbon monoxide (CO) and CH4 yield curves over time are as shown in Figure 5 and Figure 6 Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 and Ni 0.35 -W 18 O 49 all showed improved CH4 yield relative to the original W 18 O 49 At the same time, plasmonic Au 0.7 -W 18 O4 and Ni 0.35 -W 18 O 49 showed reduced CO yield relative to the original W 18 O 49 As shown in Figure 7 , plasmonic W 18 O 49 , Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 and Ni 0.35 -W 18 O 49 photocatalytic CO2 reduction to CH4 yield was 4.115, 8.534, 9.177 and 15.43 micromoles per gram per hour (μmol / g / h), respectively, and the photocatalytic CO2 reduction to CO yield was 5.174, 3.572, 5.4 and 1.86 μmol / g / h, respectively. Plasmonic W 18 O 49 , Au 0.7 -W 18 O 49 , Ag 0.35 -W 18 O 49 and Ni 0.35 -W 18 O 49 photocatalytic CO2 reduction to CH4 selectivity was 44.28%, 70.49%, 62.56% and 89.24%, respectively.

[0053] In summary, the present application provides a full-spectrum response photocatalytic CO2 reduction to CH4 catalyst, the photocatalyst is Au, Ag or Ni metal ion doped plasmonic W 18 O 49Nanowires have strong UV-visible-near-infrared light absorption ability and rich surface oxygen vacancy concentration, which are beneficial to the adsorption and activation of CO2 molecules. At the same time, the doping of Au, Ag or Ni metal ions can effectively stabilize the CO2 generated during the photocatalytic CO2 reduction process. * CO intermediate, thereby promoting * Further hydrogenation of CO intermediates produces CH4. Therefore, Au, Ag or Ni metal ion doped plasmon W 18 O 49 The nanowires all showed a significant difference compared to the original plasmon W 18 O 49 The nanowires significantly improve the performance and selectivity of photocatalytic CO2 reduction to CH4. The photocatalyst preparation method of the present invention is simple, and the research content involved is in line with the current concept of sustainable development and has potential application prospects.

[0054] Therefore, the present invention adopts a method for preparing a full-spectrum responsive carbon dioxide reduction to methane plasmon photocatalyst of the above structure, using tungsten hexacarbonyl and silver nitrate, nickel chloride or chloroauric acid as raw materials, and preparing non-metallic plasmon W doped with different metal ions by solvothermal reaction in ethanol solution. 18 O 49 Nanowire photocatalyst. Prepared metal ion-doped non-metallic plasmon W 18 O 49 Nanowires have full spectrum absorption from ultraviolet to visible to near infrared, which is superior to most reported semiconductor photocatalytic materials. The surface of the photocatalyst has abundant oxygen vacancies, which is conducive to the adsorption and activation of CO2 molecules. At the same time, the high-energy hot electrons and holes generated by the surface plasmon resonance effect are conducive to the photocatalytic CO2 reduction reaction. The doping of Au, Ag or Ni metal ions can effectively stabilize the photocatalytic CO2 reduction process. * CO intermediates, regulating non-metallic plasmon W 18 O 49 The nanowires' photocatalytic CO2 reduction selectivity improves CH4 yield and selectivity. This photocatalytic CO2 reduction process uses only H2O as an electron donor, eliminating the waste of organic sacrificial agents and causing no environmental pollution. Furthermore, the catalyst preparation method is simple, and the research involved aligns with current sustainable development concepts, demonstrating potential application prospects.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. Application of a full-spectrum responsive metal ion-doped plasmonic photocatalyst in photocatalytic CO2 reduction to produce CH4, characterized in that: Tungsten hexacarbonyl and doped metal salts were dissolved in anhydrous ethanol and metal ion-doped plasmon W was prepared by solvothermal reaction. 18 O 49 Nanowire photocatalyst; the doped metal salt is selected from at least one of silver nitrate, nickel chloride or chloroauric acid.

2. The use of a metal ion-doped plasmonic photocatalyst with a full spectrum response according to claim 1 in photocatalytic CO2 reduction to produce CH4, characterized in that: The purity of the tungsten hexacarbonyl, silver nitrate, nickel chloride and chloroauric acid is greater than 99%; the metal ions in the doped metal salt and the final product W 18 O 49 The mass percentage is 0.15% to 1.4%.

3. The use of a metal ion-doped plasmonic photocatalyst with a full spectrum response according to claim 1 in photocatalytic CO2 reduction to produce CH4, characterized in that: The concentration of the tungsten hexacarbonyl in anhydrous ethanol is 5-10 mg / mL; the temperature of the solvent thermal reaction is 160-190° C., and the reaction time is 12-24 hours.

4. The use of a metal ion-doped plasmonic photocatalyst with a full spectrum response according to claim 1 in photocatalytic CO2 reduction to produce CH4, characterized in that: The specific method of photocatalytic CO2 reduction to produce CH4 is: metal ion doped non-metal plasmon W 18 O 49 The photocatalyst was dispersed in deionized water, and the dispersed suspension was coated on a glass sheet and dried under infrared light. The amount of the photocatalyst was 5 mg, the amount of deionized water was 0.4 mL, and the area of ​​the glass sheet was 9.61 cm 2 ; The glass sheet was then placed in a photocatalytic reactor and sealed with a thick quartz cover; the entire reactor was purged with high-purity nitrogen to exclude air. Before the reaction, high-purity CO2 gas was filled into the reactor, and a small amount of deionized water was added to the bottom of the reactor; the purging time of the high-purity nitrogen was 20 minutes, the filling time of the high-purity CO2 was 20 minutes, and the amount of deionized water added to the bottom of the reactor was 0.2 mL; a xenon lamp was used to simulate sunlight for the light CO2 reduction experiment.

5. The use of a metal ion-doped plasmonic photocatalyst with full spectrum response according to claim 4 in photocatalytic CO2 reduction to produce CH4, characterized in that: The volume of the photocatalytic reactor is 180 mL, the power of the infrared lamp is 150 W, and the drying time is 10 minutes; the wavelength range of the xenon lamp simulating sunlight is 200-1100 nm, and the light intensity is 150-300 mW / cm 2 .

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