BNVO / VC MXene / RGO photo-thermal piezoelectric catalytic material as well as preparation method and application thereof

Abstract

The invention provides a BixNdyVO4 / V4C3MXene / RGO photo-thermal piezoelectric catalytic material as well as a preparation method and application thereof, the photo-thermal piezoelectric catalytic material is a compound of BixNdyVO4, V4C3MXene and RGO, and the ratio of x to y is 1: (0.5-0.75). The preparation method comprises the following steps: S1, mixing a multi-layer V4C3MXene dispersion liquid with a graphene oxide dispersion liquid, adding a bismuth source and a neodymium source, and stirring to obtain a reaction precursor liquid; and S2, carrying out a hydrothermal reaction on the reaction precursor solution, and washing and drying the obtained product to obtain the BNVO / VC MXene / RGO photo-thermal piezoelectric catalyst. According to the invention, the BixNdyVO4 / V4C3MXene / RGO material is utilized to improve the reduction stability of the material and the selectivity of methane generation through dark / photo-thermal carbon dioxide hydrogenation reduction.

Description

Technical Field

[0001] The present invention belongs to the field of environmental protection and solar energy functional material composite, specifically a Bi x Nd y VO4 / V4C3MXene / RGO (abbreviated as BNVO / VC MXene / RGO) photothermal piezoelectric catalytic material, preparation method and application thereof. Background Art

[0002] CH4 is an ideal derivative for CO2 reduction, which can be used as fuel, to synthesize ammonia and methanol, as a green hydrogen carrier, and as an important raw material for maintaining life on the International Space Station and Mars. However, the CO2 methanation process must be operated at very high temperatures (300-500°C) and pressures (4-30bar), and rare and expensive supported ruthenium and palladium catalysts are required to obtain high conversion rates and reaction rates. Therefore, there is an urgent need to develop a high-performance and environmentally friendly Sabatier CO2 methanation process. Summary of the invention

[0003] In order to solve the above-mentioned problems of the prior art, the present invention provides a Bi x Nd y VO4 / V4C3MXene / RGO photothermal piezoelectric catalytic material and its preparation method and application, using Bi x Nd y The piezoelectric effect of VO4 / V4C3MXene / RGO materials accelerates carrier separation and migration, and Bi x Nd y The VO4 upconversion effect allows more high-energy photons to participate in the CO2 methanation reaction, improving the reduction stability of the material and the selectivity of dark / photothermal carbon dioxide hydrogenation reduction to methane.

[0004] The present invention is achieved through the following technical solutions:

[0005] A BNVO / VC MXene / RGO photothermal piezoelectric catalytic material, wherein the photothermal piezoelectric catalytic material is Bi x Nd y Composite of VO4, V4C3 MXene and RGO, where x:y=1:(0.5-0.75).

[0006] The preparation method of the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material of the present invention comprises the following steps:

[0007] S1, mixing a dispersion of multilayer V4C3 MXene with a dispersion of graphene oxide, adding a bismuth source and a neodymium source, and stirring to obtain a reaction precursor solution;

[0008] S2, subjecting the reaction precursor solution to a hydrothermal reaction, and washing and drying the obtained product to obtain a BNVO / VC MXene / RGO photothermal piezoelectric catalyst.

[0009] Preferably, in S1, the preparation method of the multilayer V4C3 MXene is: etching V4AlC3 with HF solution, then washing and drying to obtain the multilayer V4C3 MXene.

[0010] Preferably, in S1, in the reaction precursor solution, the molar ratio of multilayer V4C3 MXene to graphene oxide is (2.5-3.08):1.

[0011] Preferably, in S1, the bismuth source and the neodymium source are Bi(NO3)3·5H2O and Nd(NO3)3·6H2O respectively.

[0012] Preferably, in S1, in terms of molar ratio, Bi:Nd=1:(0.5-0.75).

[0013] Preferably, in S1, the molar ratio of the bismuth source to the multilayer V4C3 MXene is (0.11-0.24):1.

[0014] Preferably, in S2, the temperature of the hydrothermal reaction is 180-200°C and the time is 16-18h.

[0015] Preferably, in S2, the drying temperature is 60-70°C and the time is 10-12h.

[0016] The present invention also provides the use of the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material in catalyzing carbon dioxide hydrogenation reduction to produce methane.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a Bi x Nd y VO4 / V4C3 MXene / RGO piezoelectric catalytic material, wherein the photothermal piezoelectric catalytic material is Bi x Nd y Composite of VO4, V4C3 MXene and RGO, Nd doped in BiVO4 lattice to form Bi x Nd y VO4,Bi x Nd y VO4 grows on the surface and interlayer of V4C3 MXene to form Bi x Nd yElectric field at the VO4 / V4C3 MXene / RGO heterojunction interface. Nd element doped in BiVO4 can act as a scavenger for electrons or holes, reducing the recombination rate of carriers in BiVO4, thereby improving the separation efficiency and promoting the photocatalytic reaction; in terms of light absorption, the unique electronic structure of Nd can cause upconversion characteristics, that is, the process of absorbing light with longer wavelengths (lower energy) and releasing light with shorter wavelengths (higher energy), thus achieving efficient utilization of light energy. Therefore, the upconversion mechanism of Nd can promote photoexcitation to produce more high-energy photons. At the same time, under the action of the polarization electric field formed by the Schottky junction, the V4C3-MXene surface plasmon effect and the RGO piezoelectric effect, the carriers migrate effectively, and the enriched electrons participate in the CO2 methanation reaction, which improves the stability of the V4C3-MXene matrix material, the catalytic reduction of carbon dioxide conversion rate, and the selectivity of generating methane, thus achieving Bi. x Nd y The methane production content of VO4 / V4C3 / RGO piezoelectric catalytic material by catalytic hydrogenation reduction in dark / photothermal environment is further improved.

[0019] The present invention x Nd y VO4 / V4C3 MXene / RGO piezoelectric catalytic material has piezoelectric properties, d 33 0.41nm V -1 , and the material stored 112.9 μmol g -1 electrons and 172.9 μmol g -1 The upconversion effect of Nd accounts for R=3.01% of the total activity. Nd doping can generate more photogenerated electrons, promote photothermal reduction of CO2 methanation, and has the characteristics of catalyst stability and high dark / photothermal catalytic reduction of methane yield. Therefore, it can be used in the field of catalytic hydrogenation reduction of carbon dioxide to produce methane. x Nd y VO4 / V4C3 MXene / RGO piezoelectric catalytic materials are used for dark / photothermal hydrogenation reduction of carbon dioxide to produce methane, which increases the methane content generated by photothermal reduction of V4C3 MXene-based catalytic materials. Tests show that the methane yield under photothermal conditions is as high as 229.9 μmol·g -1 ·h -1 , respectively, than BiVO4 / V4C3 / RGO and Bi x Nd y VO4 catalyst increased by 2.3 and 10.6 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 Bi prepared in the present invention x Nd y XRD pattern of VO4 / V4C3 MXene / RGO material;

[0022] Figure 2 Bi prepared in Example 2 x Nd y SEM image of VO4 / V4C3 MXene / RGO;

[0023] Figure 3 Bi prepared in Comparative Example 3 x Nd y SEM image of VO4;

[0024] Figure 4 Bi prepared in Example 2 x Nd y Absorbance curve of methylene blue degradation by VO4 / V4C3 MXene / RGO under dark conditions;

[0025] Figure 5 Bi prepared in Example 2 x Nd y EPR-h of VO4 / V4C3 MXene / RGO under dark conditions + spectrum;

[0026] Figure 6 Bi prepared in Example 2 x Nd y VO4 / V4C3 MXene / RGO phase shift and amplitude-voltage curves;

[0027] Figure 7 Bi prepared in the present invention x Nd y Dark hydrogenation reduction of CO2 activity diagram of VO4 / V4C3 MXene / RGO;

[0028] Figure 8 Bi prepared in the present invention x Nd y UV-Vis-NIR absorption spectra of VO4 / V4C3 MXene / RGO materials;

[0029] Fig. 9 Bi prepared in the present invention x Nd y Local magnified image of light absorption of VO4 / V4C3 MXene / RGO material at 200-800nm;

[0030] Fig.10 Bi prepared in the present invention x Nd y Photocatalytic reduction of CO2 activity of VO4 / V4C3 MXene / RGO under different monochromatic light irradiation;

[0031] Fig.11 Bi prepared in the present invention x Nd y Activity diagram of photothermal hydrogenation reduction of CO2 by VO4 / V4C3 MXene / RGO;

[0032] Fig.12 Bi prepared in Example 2 x Nd y Photothermal cycle activity diagram of VO4 / V4C3 MXene / RGO. DETAILED DESCRIPTION

[0033] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0035] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0036] Embodiment 1:

[0037] Step 1: Slowly add 2g V4AlC3 to 40mL of 49% HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0038] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.025mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0039] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 12 hours to obtain Bi1Nd 0.05 Materials of VO4 / V4C3 MXene / RGO.

[0040] Photothermal CO2 hydrogenation test:

[0041] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.05 The VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. While ensuring that the atmospheric pressure photothermal catalytic device is leak-proof, the atmospheric pressure photothermal catalytic device is heated to 250°C, the culture dish is placed in the atmospheric pressure photothermal catalytic device, and an inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the atmospheric pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0042] Embodiment 2:

[0043] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0044] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0045] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 12 hours to obtain Bi1Nd 0.10 Materials of VO4 / V4C3 MXene / RGO.

[0046] Carbon dioxide hydrogenation test at room temperature in the dark:

[0047] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.10 VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, and stirred and dispersed, and then placed in a dark environment at room temperature to dry naturally before being taken out for use. The culture dish is placed in the normal-pressure photothermal catalytic device while ensuring that the normal-pressure photothermal catalytic device does not leak. The top of the normal-pressure photothermal catalytic device is shielded with a stainless steel iron plate to ensure a dark environment. After the inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min), the inlet and outlet valves are closed, and 20mL of carbon dioxide gas and 60mL of hydrogen are filled into the normal-pressure photothermal catalytic device. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content.

[0048] Carbon dioxide hydrogenation test in a dark environment at 250℃:

[0049] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.10VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. The normal pressure photothermal catalytic device is heated to 250°C, and the culture dish is placed in the normal pressure photothermal catalytic device while ensuring that the normal pressure photothermal catalytic device does not leak. The top of the normal pressure photothermal catalytic device is shielded with a stainless steel iron plate to ensure a dark environment. After the inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min), the inlet and outlet valves are closed, and 20mL of carbon dioxide gas and 60mL of hydrogen are filled into the normal pressure photothermal catalytic device. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the auxiliary heat temperature is 250°C.

[0050] Photothermal CO2 hydrogenation test:

[0051] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.10 The VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. While ensuring that the atmospheric pressure photothermal catalytic device is leak-proof, the atmospheric pressure photothermal catalytic device is heated to 250°C, the culture dish is placed in the atmospheric pressure photothermal catalytic device, and an inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the atmospheric pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0052] Embodiment 3:

[0053] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0054] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.125mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0055] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 12 hours to obtain Bi1Nd 0.25 Materials of VO4 / V4C3 MXene / RGO.

[0056] Photothermal CO2 hydrogenation test:

[0057] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.25 The VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. While ensuring that the atmospheric pressure photothermal catalytic device is leak-proof, the atmospheric pressure photothermal catalytic device is heated to 250°C, the culture dish is placed in the atmospheric pressure photothermal catalytic device, and an inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the atmospheric pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0058] Embodiment 4:

[0059] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0060] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.25mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0061] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 12 hours to obtain Bi1Nd 0.50 Materials of VO4 / V4C3 MXene / RGO.

[0062] Photothermal CO2 hydrogenation test:

[0063] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.50 The VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. While ensuring that the atmospheric pressure photothermal catalytic device is leak-proof, the atmospheric pressure photothermal catalytic device is heated to 250°C, the culture dish is placed in the atmospheric pressure photothermal catalytic device, and an inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the atmospheric pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0064] Embodiment 5:

[0065] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0066] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.375mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0067] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 12 hours to obtain Bi1Nd 0.75 Materials of VO4 / V4C3 MXene / RGO.

[0068] Photothermal CO2 hydrogenation test:

[0069] The existing homemade glass cup is inverted, and the concave portion with a diameter of 40 mm at the upper end can be regarded as a culture dish. 60 mg of Bi1Nd 0.75 The VO4 / V4C3 MXene / RGO material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. While ensuring that the atmospheric pressure photothermal catalytic device is leak-proof, the atmospheric pressure photothermal catalytic device is heated to 250°C, the culture dish is placed in the atmospheric pressure photothermal catalytic device, and an inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the atmospheric pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0070] Embodiment 6:

[0071] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0072] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.070mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0073] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 10 hours to obtain Bi1Nd 0.10 Materials of VO4 / V4C3 MXene / RGO.

[0074] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0075] Embodiment 7:

[0076] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0077] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 1.725mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0078] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0079] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0080] Embodiment 8:

[0081] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0082] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0083] Step 3, the mixed system was subjected to hydrothermal reaction at 180°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0084] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0085] Embodiment 9:

[0086] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0087] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0088] Step 3, the mixed system was subjected to hydrothermal reaction at 190°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0089] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0090] Embodiment 10:

[0091] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0092] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0093] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 16 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0094] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0095] Embodiment 11:

[0096] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0097] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0098] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 17 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0099] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0100] Embodiment 12:

[0101] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0102] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0103] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 60°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0104] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0105] Embodiment 13:

[0106] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0107] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0108] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 10 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0109] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0110] Embodiment 14:

[0111] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0112] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0113] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 11 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0114] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0115] Embodiment 15:

[0116] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0117] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.50mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Nd(NO3)3·6H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0118] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours, and after the reaction temperature dropped to room temperature, the reactor was taken out, the supernatant was removed, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 70°C for 12 hours to obtain Bi1Nd 0.10 VO4 / V4C3 MXene / RGO materials.

[0119] The photothermal carbon dioxide hydrogenation test was carried out according to the method of Example 1.

[0120] Comparative Example 1:

[0121] 2 g of V4AlC3 was slowly added to 40 mL of HF solution to form a mixed solution. After stirring evenly at room temperature, it was placed in a 55 °C water bath and heated and stirred for 96 h. The resulting mixed system was centrifuged and the precipitate was washed with deionized water until the pH of the supernatant was 7. The precipitate was dried and ground to obtain multilayer V4C3 MXene powder.

[0122] Comparative Example 2:

[0123] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0124] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 2.125mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, add 0.50mmoL of Bi(NO3)3·5H2O, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0125] Step 3, the mixed system is subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction is completed and the temperature drops to room temperature, the reactor is taken out and allowed to stand to remove the supernatant. The precipitate is washed with deionized water and anhydrous ethanol for three times, respectively, and dried at 65°C for 12 hours after centrifugation to obtain a material named BiVO4 / V4C3 MXene / RGO.

[0126] Carbon dioxide hydrogenation test at room temperature in the dark:

[0127] The existing homemade glass cup is inverted, and the concave part with a diameter of 40mm at the upper end can be regarded as a culture dish. 60mg of BiVO4 / V4C3 MXene / RGO material of this comparative example 2 is taken into the culture dish, and a small amount of deionized water is added to stir and disperse, and then placed in a dark environment at room temperature to dry naturally and then taken out for use. The culture dish is placed in the normal pressure photothermal catalytic device while ensuring that the normal pressure photothermal catalytic device does not leak, and the top of the normal pressure photothermal catalytic device is shielded with a stainless steel iron plate to ensure a dark environment. After the inert gas is continuously passed through the device for 10min (the flow rate is 2mL / min), the inlet and outlet valves are closed, and 20mL of carbon dioxide gas and 60mL of hydrogen are filled into the normal pressure photothermal catalytic device. The pressure after inflation is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content.

[0128] Carbon dioxide hydrogenation test in a dark environment at 250℃:

[0129] The existing homemade glass cup is inverted, and the concave part with a diameter of 40mm at the upper end can be regarded as a culture dish. 60mg of BiVO4 / V4C3 MXene / RGO material of this comparative example 2 is taken into the culture dish, and a small amount of deionized water is added to stir and disperse, and then placed in a vacuum oven, dried under a vacuum environment of 65°C and taken out for use. The normal pressure photothermal catalytic device is heated to 250°C, and the culture dish is placed in the normal pressure photothermal catalytic device while ensuring that the normal pressure photothermal catalytic device does not leak. The top of the normal pressure photothermal catalytic device is shielded with a stainless steel iron plate to ensure a dark environment. After the inert gas is continuously passed through the device for 10min (the flow rate is 2mL / min), the inlet and outlet valves are closed, and 20mL of carbon dioxide gas and 60mL of hydrogen are filled into the normal pressure photothermal catalytic device. The pressure after inflation is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the auxiliary heat temperature is 250°C.

[0130] Photothermal CO2 hydrogenation test:

[0131] The existing homemade glass cup is inverted, and the concave part with a diameter of 40mm at the upper end can be regarded as a culture dish. 60mg of BiVO4 / V4C3 MXene / RGO material of this comparative example 2 is taken into the culture dish, and a small amount of deionized water is added to stir and disperse, and then placed in a vacuum oven, and taken out for use after drying under a vacuum environment of 65°C. The normal pressure photothermal catalytic device is heated to 250°C while ensuring that the normal pressure photothermal catalytic device does not leak, and the culture dish is placed in the normal pressure photothermal catalytic device. After the inert gas is continuously passed through the device for 10min (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the normal pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after inflation is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0132] Comparative Example 3:

[0133] Step 1: Slowly add 2g V4AlC3 to 40mL HF solution to form a mixed solution. After stirring evenly at room temperature, place it in a 55°C water bath and heat and stir for 96 hours. Centrifuge the resulting mixed system and wash the precipitate with deionized water until the pH of the supernatant is 7. Dry the precipitate and grind it to obtain multilayer V4C3 MXene powder.

[0134] Step 2: Disperse 3.45mmoL of graphene oxide into 100mL of deionized water and stir ultrasonically for 30min to form a uniform graphene oxide dispersion; dissolve 1.25mmoL of V4C3 MXene powder in 40mL of deionized water, stir evenly, add 20mL of graphene oxide dispersion, continue to stir evenly, then add 0.25mmoL of Bi(NO3)3·5H2O and 0.05mmoL of Bi(NO3)3·5H2O in sequence, stir until completely dissolved, and mix evenly to obtain a mixed system;

[0135] Step 3, the mixed system was subjected to hydrothermal reaction at 200°C for 18 hours. After the reaction temperature dropped to room temperature, the reactor was taken out and the supernatant was removed. The precipitate was washed with deionized water and anhydrous ethanol for 3 times, centrifuged and dried at 65°C for 12 hours to obtain Bi1Nd 0.10 VO4 material.

[0136] Carbon dioxide hydrogenation test at room temperature in the dark:

[0137] The existing homemade glass cup was inverted, and the concave portion with a diameter of 40 mm at the upper end was regarded as a culture dish. 60 mg of Bi1Nd 0.10 The VO4 material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a dark environment at room temperature to dry naturally before being taken out for use. The culture dish is placed in the normal-pressure photothermal catalytic device while ensuring that the normal-pressure photothermal catalytic device does not leak. The top of the normal-pressure photothermal catalytic device is shielded with a stainless steel iron plate to ensure a dark environment. After the inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min), the inlet and outlet valves are closed, and 20mL of carbon dioxide gas and 60mL of hydrogen are filled into the normal-pressure photothermal catalytic device. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content.

[0138] Carbon dioxide hydrogenation test in a dark environment at 250℃:

[0139] The existing homemade glass cup was inverted, and the concave portion with a diameter of 40 mm at the upper end was regarded as a culture dish. 60 mg of Bi1Nd 0.10The VO4 material is placed in the culture dish, a small amount of deionized water is added, stirred and dispersed, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. The normal-pressure photothermal catalytic device is heated to 250°C, and the culture dish is placed in the normal-pressure photothermal catalytic device while ensuring that the normal-pressure photothermal catalytic device does not leak. The top of the normal-pressure photothermal catalytic device is shielded with a stainless steel iron plate to ensure a dark environment. After the inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min), the inlet and outlet valves are closed, and 20mL of carbon dioxide gas and 60mL of hydrogen are filled into the normal-pressure photothermal catalytic device. The pressure after filling is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the auxiliary heat temperature is 250°C.

[0140] Photothermal CO2 hydrogenation test:

[0141] The existing homemade glass cup was inverted, and the concave portion with a diameter of 40 mm at the upper end was regarded as a culture dish. 60 mg of Bi1Nd 0.10 The VO4 material is placed in the culture dish, stirred and dispersed with a small amount of deionized water, and then placed in a vacuum oven, dried under a vacuum environment of 65°C, and taken out for use. While ensuring that the normal-pressure photothermal catalytic device is leak-proof, the normal-pressure photothermal catalytic device is heated to 250°C, the culture dish is placed in the normal-pressure photothermal catalytic device, and an inert gas is continuously passed through the device for 10 minutes (the flow rate is 2mL / min). Close the inlet and outlet valves, and fill the normal-pressure photothermal catalytic device with 20mL of carbon dioxide gas and 60mL of hydrogen. The pressure after inflation is 0.12MPa. React for 3 hours, and take a sample (1mL) into the gas chromatograph every hour to detect the carbon monoxide and methane content. Among them, the light source uses a 300W xenon lamp, and the auxiliary heat temperature is 250°C.

[0142] The following is a detailed description of the figures appearing in the present invention.

[0143] Figure 1 Bi prepared in the present invention x Nd y XRD patterns of VO4 / V4C3 MXene / RGO materials. a and b are V4C3 MXene and BiVO4 / V4C3 MXene / RGO synthesized according to Comparative Examples 1-2, respectively, and d, e, f and g are Bi x Nd yVO4 / V4C3 MXene / RGO piezoelectric catalyst. The diffraction peaks at 2θ=7.8° and 15.6° correspond to the (002) and (004) crystal planes of V4C3-MXene, respectively. The diffraction peaks at 2θ=18.9°, 28.9°, 30.5°, 40.2°, 42.4°, 47.2° and 53.2° are respectively attributed to the (011), (112), (004), (121) and (015) crystal planes of monoclinic BiVO4 (PDF#83-1700), and there are no impurity peaks related to the Nd element. It is inferred that this may be due to the low content or the presence of Nd. 3+ With the Nd 3+ As the content increases, the diffraction peak corresponding to BiVO4 becomes broadened, which indicates that the grain size of the sample gradually decreases.

[0144] Figure 2 Bi1Nd prepared in Example 2 0.10 SEM image of VO4 / V4C3 MXene / RGO. It can be seen from the figure that the interlayer spacing of the layered V4C3-MXene becomes larger, and irregular rod-shaped and sheet-shaped structures grow in situ between its layers and on its surface, and a small amount of nanoparticles are attached to the surface of V4C3 MXene.

[0145] Figure 3 Bi1Nd prepared in Comparative Example 3 0.10 SEM image of VO4.Bi1Nd 0.10 The irregular polygonal flake structure displayed by VO4 is composed of thin sheets stacked on top of each other, and also contains a large number of agglomerated nanoparticle morphologies. It is speculated that this is because the addition of Nd inhibits the oriented growth of grains.

[0146] Figure 4 Bi1Nd prepared in Example 2 0.10 The absorbance curve of VO4 / V4C3 MXene / RGO degrading methylene blue under dark conditions shows that its own stored electron concentration is 112.9 μmol·g -1 .

[0147] Figure 5 Bi1Nd prepared in Example 2 0.10 EPR-h of VO4 / V4C3 MXene / RGO under dark conditions + The quantum spin number of Bi1Nd prepared in Example 2 was calculated by EPR spectrum. 0.10 h released by VO4 / V4C3 MXene / RGO within 20 min + The concentrations were 172.9 μmol g -1 It can be seen that TEMPO-h+ The intensity of the characteristic signal decreases with the extension of the test time, which indicates that the catalyst can release more h + , proving that a large amount of h is stored on the crystal surface + .

[0148] Figure 6 Bi1Nd prepared in Example 2 0.10 Phase shift and amplitude-voltage curves of VO4 / V4C3 MXene / RGO. The amplitude-voltage curves show a typical "butterfly ring", which is an established feature of ferroelectric materials. These results demonstrate the piezoelectric properties of the prepared materials and provide strong evidence for the intrinsic polarization electric field within their structure. In addition, the piezoelectric coefficient value (d 33 ) is about 0.41nm·V -1 .

[0149] Figure 7 Bi prepared in the present invention x Nd y Dark hydrogenation reduction of CO2 activity diagram of VO4 / / V4C3 MXene / RGO. b and h are BiVO4 / V4C3 MXene / RGO and Bi1Nd synthesized according to comparative examples 2-3, respectively. 0.10 VO4,d is Bi1Nd synthesized according to Example 2 0.10 VO4 / V4C3 MXene / RGO piezoelectric catalyst. The yields of CO produced by catalytic reduction of CO2 by samples b, d and h in the dark were 32.49, 36.17 and 13.47 μmol·g, respectively. cat -1 ·h -1 Among them, sample d has 5.62 μmol·g cat -1 ·h -1 Methane generation. The CO yields of samples b, d, and h in a light-free and heat-free environment were 10.75, 14.52, and 7.69 μmol·g, respectively. cat -1 ·h -1 (Error bars are the standard deviations of three independent tests). Sample d exhibited higher reduction activity in the dark, which was presumably due to the piezoelectric effect of RGO.

[0150] Figure 8 Bi prepared in the present invention x Nd y UV-visible-near infrared absorption spectra of VO4 / V4C3 MXene / RGO materials. b and h are BiVO4 / V4C3 MXene / RGO and Bi1Nd synthesized according to Comparative Examples 2-3, respectively. 0.10VO4, and c, d, e, f and g are Bi synthesized according to Examples 1-5, respectively. x Nd y VO4 / V4C3MXene / RGO piezoelectric catalyst. Bi x Nd y VO4 / V4C3MXene / RGO has stable and enhanced light absorption in the full spectrum. 0.10 VO4) samples have strong absorption mainly in the ultraviolet range, and the absorption edge falls at 526nm.

[0151] Fig. 9 Bi prepared in the present invention x Nd y A local magnified image of the light absorption of VO4 / V4C3 MXene / RGO material at 200-800nm. b and h are BiVO4 / V4C3MXene / RGO and Bi1Nd synthesized according to Comparative Examples 2-3, respectively. 0.10 VO4, and c, d, e, f and g are Bi synthesized according to Examples 1-5, respectively. x Nd y VO4 / V4C3 MXene / RGO piezoelectric catalyst. As can be seen from the figure, the light absorption magnification of all doped samples at 200-800nm ​​is 3+ In the BiVO4 sample, 593nm, 687nm and 754nm are caused by Nd 3+ The ground state 4I 9 / 2 Excited to excited state 4G 5 / 2 、4F 9 / 2 and 4F 7 / 2 Compared with the light absorption graph of BiVO4 / V4C3 MXene / RGO, the light absorption rise of the doped sample can be attributed to the Nd 3+ The light absorption enhancement phenomenon caused by the impurity energy level formed in BiVO4. The light absorption intensity of sample d is higher than that of samples with other doping amounts. When the Nd concentration is high, Bi x Nd y The reason for the decrease in the light absorption intensity of VO4 / V4C3 MXene / RGO may be that the high Nd concentration leads to the 3+ Clusters are formed and self-quenching occurs, and this concentration quenching process is detrimental to the upconversion efficiency.

[0152] Fig.10 Bi prepared in the present invention x Nd yPhotocatalytic reduction of CO2 yields of VO4 / V4C3 MXene / RGO under different monochromatic light irradiation. Where b is BiVO4 / V4C3 MXene / RGO synthesized according to Comparative Example 2, d is Bi1Nd 0.10 VO4 / V4C3 MXene / RGO piezoelectric catalyst. When the catalyst was irradiated with monochromatic light of wavelengths of 740, 850, 940, and 1100 nm, the photocatalytic reduction yields of CO2 in sample d were 2.2, 3.5, 6.4, and 4.1 μmol·g, respectively. cat -1 ·h -1 The reduction yields of sample b at different wavelengths were 4.1, 3.2, 2.4, and 1.7 mol·g cat -1 ·h -1 Since the up-conversion property of Nd can convert near-infrared light into absorbable visible light, Example 2 can absorb light with wavelengths of 940 and 1100 nm and release it as short-wavelength light of 740 and 850 nm. Combined with the calculation formula, it can be known that the proportion of Nd up-conversion effect in the total activity is R=3.01%, indicating that Nd doping can generate more photogenerated electrons and promote photothermal reduction of CO2 methanation.

[0153] Fig.11 Bi prepared in the present invention x Nd y Activity diagram of photothermal hydrogenation reduction of CO2 by VO4 / V4C3 MXene / RGO. b and h are BiVO4 / V4C3 MXene / RGO and Bi1Nd synthesized according to comparative examples 2-3, respectively. 0.10 VO4, and c, d, e, f and g are Bi synthesized according to Examples 1-5, respectively. x Nd y VO4 / V4C3MXene / RGO piezoelectric catalyst. The yields of photothermal reduction of CO2 to CH4 are 99.40, 181.68, 229.9, 178.27, 145.49, 130.83 and 21.56 μmol·g, respectively. cat -1 ·h -1 After the introduction of Nd, the CH4 yield increased, and the yield of the best sample d was 2.3 and 10.6 times that of b and h, respectively.

[0154] Fig.12 Bi1Nd prepared in Example 2 0.10 VO4 / V4C3 MXene / RGO photothermal cycle activity diagram. Example 2 The photothermal reduction CO2 yield remained at a high level after 6 cycles, indicating that the Bi x Ndy The VO4 / V4C3 MXene / RGO heterojunction photothermal catalyst has good photothermal conversion ability and cycle stability. Therefore, the photothermal hydrogenation reduction of carbon dioxide conversion rate of this material can maintain long-term stability.

Claims

1. A BNVO / VC MXene / RGO photothermal piezoelectric catalytic material, characterized in that: The photothermal piezoelectric catalytic material is Bi x Nd y Composite of VO4, V4C3 MXene and RGO, where x:y=1:(0.5-0.75).

2. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 1, characterized in that: The steps include: S1, mixing a dispersion of multilayer V4C3 MXene with a dispersion of graphene oxide, adding a bismuth source and a neodymium source, and stirring to obtain a reaction precursor solution; S2, subjecting the reaction precursor solution to a hydrothermal reaction, and washing and drying the obtained product to obtain a BNVO / VC MXene / RGO photothermal piezoelectric catalyst.

3. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S1, the preparation method of the multilayer V4C3 MXene is: V4AlC3 is acid-etched with HF solution, and then washed with water and dried to obtain the multilayer V4C3 MXene.

4. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S1, the molar ratio of multilayer V4C3 MXene to graphene oxide in the reaction precursor solution is (2.5-3.08):

1.

5. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S1, the bismuth source and neodymium source are Bi(NO3)3·5H2O and Nd(NO3)3·6H2O respectively.

6. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S1, Bi:Nd=1:(0.5-0.75) in terms of molar ratio.

7. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S1, the molar ratio of the bismuth source to the multilayer V4C3 MXene is (0.11-0.24):

1.

8. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S2, the temperature of the hydrothermal reaction is 180-200°C and the time is 16-18h.

9. The method for preparing the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 2, characterized in that: In S2, the drying temperature is 60-70°C and the time is 10-12h.

10. Use of the BNVO / VC MXene / RGO photothermal piezoelectric catalytic material according to claim 1 in catalytic carbon dioxide hydrogenation reduction to produce methane.

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