High-entropy perovskite composite photocatalytic material for carbon dioxide reduction as well as preparation method and application of high-entropy perovskite composite photocatalytic material

Abstract

The invention belongs to the technical field of preparation and application of catalytic materials, and particularly relates to a high-entropy perovskite composite photocatalytic material for carbon dioxide reduction as well as a preparation method and application of the high-entropy perovskite composite photocatalytic material. The photocatalytic material disclosed by the invention is a material which is formed by compounding (Bi < 0.2 > Na < 0.2 > K < 0.2 > Ca < 0.2 > Sm < 0.2 >) TiO < 3 > and Bi < 2 > WO < 6 > and has an S-type heterostructure. According to the photocatalytic material, high-entropy perovskite rich in oxygen vacancies serves as a substrate, Bi2WO6 with excellent CO2 adsorption performance grows on the surface of the substrate in situ, an S-type heterojunction with chemical bonds serving as electron transmission bridges is formed, and the composite material has higher electron-hole separation and transmission efficiency and higher catalytic activity and stability; according to the preparation method, special equipment and harsh conditions are not needed, meanwhile, element controllability of the high-entropy perovskite structure is high, directional regulation and control of the structure-function relationship can be achieved, and the preparation method has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic material preparation and application, and specifically relates to a high-entropy perovskite composite photocatalytic material for carbon dioxide reduction, and a preparation method and application thereof. Background Art

[0002] Global climate change and the energy crisis are major challenges facing humanity in the 21st century. Since the Industrial Revolution, the overuse of fossil fuels has caused atmospheric CO2 concentrations to surge from 280 ppm to over 420 ppm, triggering problems such as the intensified greenhouse effect and ocean acidification. At the same time, the non-renewable nature of traditional energy sources has prompted people to seek alternative sustainable development solutions. Using clean energy, solar energy, to drive photocatalytic materials to reduce carbon dioxide and convert it into hydrocarbon fuels such as methane and methanol can not only achieve resource utilization of greenhouse gases, but also store solar energy as chemical energy. This is of great strategic significance for alleviating the contradiction between energy supply and demand and improving the ecological environment. In the future, through catalyst design and reactor engineering optimization, photocatalytic CO2 reduction is expected to become an important technical path for green chemical industry and clean energy production. However, its practical application still faces key issues such as low catalytic efficiency and insufficient stability.

[0003] High-entropy perovskite oxides are a new type of multi-component oxide composed of five or more different metal ions occupying the A or B sites. Their configurational entropy exceeds 1.61R, resulting in a unique chemical disorder. This disorder leads to lattice distortion and the coexistence of mixed valence states of multiple metal ions. Lattice distortion promotes the formation of oxygen vacancies by reducing the oxygen ion migration barrier. Oxygen vacancies can act as electron traps to suppress carrier recombination and adsorb and activate reactive molecules. Further, by constructing heterojunctions through chemical bond bridging, the electron transport bottleneck caused by the traditional heterojunction's reliance on physical adsorption is overcome, forming a continuous low-barrier transmission channel and significantly accelerating the reaction kinetics.

[0004] Patent CN 119456053A uses electrospinning and calcination to prepare a high-entropy perovskite catalyst La(MMn)O3, where M is a mixture of Ni, Cu, Co, and Fe. This produces a rod-like structure of nanoparticle stacking, significantly improving conductivity and charge transfer rate while increasing the surface area of ​​the catalyst and enhancing catalytic performance. Patent CN 115837275A discloses a perovskite-type high-entropy oxide with one of La, Ca, Sr, or Ba at the A position and five or more of Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr, or Mo at the B position, as well as its preparation method and application. The catalyst exhibits good activity and stability in the pressurized methanation reaction of carbon monoxide and carbon dioxide. These high-entropy perovskite catalysts all exhibit good catalytic performance due to the high-entropy effect, but they are all single-system catalysts. By introducing a second phase to construct a heterojunction, it is expected to further promote the separation efficiency of electrons and holes, thereby improving the catalytic performance. Patent CN 113663679A doped Co in LaNiO3 to obtain LaNi x Co 1-x O3, and then LaNi x Co 1-x O3 and CeO2 are combined to effectively adjust the energy level matching of the photocatalyst and expand the light response range; Patent CN 114433126A synthesizes a high entropy perovskite monolithic catalyst La(M X Co)O3@PAC, where M is any four of the metal elements Al, Mn, Fe, Ni, Cu, Zn, and Ti, produces highly active free radicals during the catalytic process, effectively removing organic pollutants. However, these composite catalysts all form complexes through interfacial interactions, with heterojunctions acting as the interfacial interaction. While this promotes electron-hole separation, the electron transfer efficiency remains low compared to using chemical bonds as the electron transport bridge, limiting their catalytic performance.

[0005] In comparison, the high entropy effect of high-entropy perovskites and the construction of heterojunctions through chemical bond bridging can effectively improve the efficiency of electron transfer, inhibit the recombination of photogenerated electron-hole pairs, change the reaction kinetics, and reduce the energy barrier of the reaction. For example, Liu et al. (Solar RRL 5 (2021) 20062) prepared a heterostructure by in-situ growth of Cs3Bi2I9 on ultra-thin Bi2WO6, which showed excellent performance compared with the heterostructure produced by physical mixing. This in-situ growth strategy promotes the co-sharing of Bi atoms, thereby enhancing the interface proximity and strong electronic interaction between semiconductors, thereby promoting efficient charge transfer, thereby effectively realizing photocatalytic CO2 reduction. Summary of the Invention

[0006] Aiming at the bottleneck problems of low carrier migration efficiency, poor photocatalytic stability and poor product selectivity in the existing photocatalytic CO2 reduction technology, the present invention provides a new high entropy perovskite-based composite photocatalytic material Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 heterojunction system. This invention uses a sol-gel method combined with a solid-phase reaction method to prepare a composite photocatalytic material with high electron-hole separation and migration efficiency, high carbon dioxide reduction activity and stability, and an S-shaped heterostructure bridged by chemical bonds. Its use in the photocatalytic reduction of carbon dioxide can increase carbon monoxide yield by 5-8 times.

[0007] To achieve the above object, the technical solution of the present invention is as follows: A high entropy perovskite composite photocatalytic material for carbon dioxide reduction, which is composed of (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )A material with an S-type heterostructure composed of TiO3 and Bi2WO6.

[0008] Furthermore, the (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )The molar ratio of TiO3 and Bi2WO6 is 50:10~1.

[0009] The method for preparing the high entropy perovskite composite photocatalytic material as described above comprises the following steps: Step 1: dissolving citric acid in deionized water to obtain a citric acid solution; Step 2: Add ammonia water to the citric acid solution and adjust the pH to obtain ammonium citrate solution (as a chelating agent); Step 3: adding tetrabutyl titanate and acetylacetone to the ammonium citrate solution, stirring, and separating to obtain a titanium citrate solution; Step 4: Add Bi(NO3)3·5H2O, NaNO3, KNO3, Ca(NO3)2, and Sm(NO3)3·6H2O to the titanium citrate solution, stir, and dehydrate to form a sol; Step 5: heating the obtained sol to obtain a gel; Step 6: The obtained gel is subjected to solid phase reaction to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2Sm 0.2 )TiO3; Step 7: Add Bi(NO3)3·5H2O and Na2WO4⋅2H2O to deionized water and stir to dissolve to obtain a white suspension; Step 8: 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 was added to the white suspension for hydrothermal reaction to obtain Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3, which is the high entropy perovskite composite photocatalytic material.

[0010] Furthermore, in step 1, the mass ratio of citric acid to deionized water is 1:1-4; in step 2, the concentration of ammonia water is 10-28%, and the pH is adjusted to 8.

[0011] Furthermore, in step 3, the volume ratio of tetrabutyl titanate to acetylacetone is 1:1; the stirring temperature is 60-80° C., and the stirring time is 5-8 hours.

[0012] Furthermore, in step 4, the molar ratio of Bi(NO3)3·5H2O, NaNO3, KNO3, Ca(NO3)2, Sm(NO3)3·6H2O and titanium citrate is 0.2:0.2:0.2:0.2:0.2:1; the stirring temperature is 80-100°C, and the time is 5-8h.

[0013] Furthermore, the heating temperature in step 5 is 160° C. and the heating time is 10 to 12 hours; and the solid phase reaction temperature in step 6 is 600 to 1000° C. and the heating time is 2 to 4 hours.

[0014] Furthermore, in step 7, the molar ratio of Bi(NO3)3·5H2O and Na2WO4·2H2O is 1~2:1, and the stirring time is 1~2h.

[0015] Furthermore, the temperature of the hydrothermal reaction in step 8 is 120° C., and the time is 12 to 14 hours.

[0016] The application of the high entropy perovskite composite photocatalytic material as described above in photocatalytic carbon dioxide reduction.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The synergistic effect of the intrinsic active sites such as oxygen vacancies in high-entropy perovskites and the interface engineering of chemical bond bridging achieves a multi-dimensional improvement in charge separation and surface reaction efficiency, providing new ideas for the design of efficient photocatalytic systems.

[0018] 2. The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 catalyst is an S-type heterostructure, and the electrons in the Bi2WO6 conduction band migrate to (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 valence band to recombine with holes, significantly promoting the separation efficiency of photogenerated electrons and holes.

[0019] 3. Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalyst, due to the chemical bond formed at the interface, the interaction makes Bi2WO6 not form a flower-like structure, but is evenly coated on (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 surface, which is conducive to the adsorption of CO2.

[0020] 4. The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalyst can reduce CO2 to CO with high efficiency in the absence of any sacrificial agent and photosensitizer, and the CO yield can reach 35.8μmol•g-1•h-1, which is the highest among pure (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3, 6.35 times that of Bi2WO6, and has high selectivity and good cycle stability.

[0021] 5. The preparation method described in the present invention is a sol-gel method combined with a solid-phase reaction, and a heterojunction is constructed through an in-situ hydrothermal reaction. Without the need for precious metals, light absorption, charge separation and surface reaction can be synergistically regulated through flexible replacement of A / B site elements and chemical disorder, achieving low-cost and high-efficiency photocatalysis, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1 and (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) XRD spectrum of TiO3 material; Figure 2 The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1 and (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) SEM spectrum of TiO3 material; Figure 3 The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1, (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 material and Comparative Example 3 (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )Photocatalytic reduction of CO2 performance of TiO3+Bi2WO6. DETAILED DESCRIPTION

[0023] To facilitate understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Example 1

[0024] A Bi2WO6 / (Bi2WO6) composite for carbon dioxide reduction using chemical bonds as electron transfer bridges 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) A method for preparing a TiO3 composite photocatalytic material, comprising the following steps: Step 1: Add 10 g of citric acid to 30 ml of deionized water and stir at 400 rpm for 1 hour to fully dissolve to obtain a citric acid solution; Step 2: Add 20% ammonia water to the citric acid solution and adjust the pH to 8 to obtain an ammonium citrate solution; Step 3: Add 10 ml of tetrabutyl titanate and 10 ml of acetylacetone to the ammonium citrate solution and stir at 60°C for 5 h to obtain a light yellow double-layer solution, and separate a transparent titanium citrate solution; Step 4: Add 2.84 g of Bi(NO3)3·5H2O, 0.50 g of NaNO3, 0.59 g of KNO3, 0.96 g of Ca(NO3)2, and 2.61 g of Sm(NO3)3·6H2O to the titanium citrate solution, stir at 100°C for 5 h, and dehydrate to form a sol; Step 5: Heat the obtained sol at 160°C for 10 h to obtain a black xerogel; Step 6: Grind the obtained gel thoroughly and place it in a muffle furnace at 700℃ for solid phase reaction for 2h to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) TiO3; Step 7: Add 0.33 g of Bi(NO3)3·5H2O and 0.11 g of Na2WO4⋅2H2O to 50 ml of deionized water and stir to dissolve to obtain a white suspension; Step 8: 1g of (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2)TiO3 was added to the white suspension, and the mixed solution was added to a polytetrafluoroethylene-lined reactor, and a hydrothermal reaction was carried out at 120 ° C for 12 h to obtain a composite photocatalytic material Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3. Example 2

[0025] A Bi2WO6 / (Bi2WO6) composite for carbon dioxide reduction using chemical bonds as electron transfer bridges 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) A method for preparing a TiO3 composite photocatalytic material, comprising the following steps: Step 1: Add 10 g of citric acid to 40 ml of deionized water and stir at 400 rpm for 1 h to fully dissolve to obtain a citric acid solution; Step 2: Add 25% ammonia water to the citric acid solution and adjust the pH to 8 to obtain an ammonium citrate solution; Step 3: Add 10 ml of tetrabutyl titanate and 10 ml of acetylacetone to the ammonium citrate solution and stir at 70°C for 6 h to obtain a light yellow double-layer solution, and separate a transparent titanium citrate solution; Step 4: Add 2.84 g of Bi(NO3)3·5H2O, 0.50 g of NaNO3, 0.59 g of KNO3, 0.96 g of Ca(NO3)2, and 2.61 g of Sm(NO3)3·6H2O to the titanium citrate solution, stir at 90°C for 6 h, and dehydrate to form a sol; Step 5: Heat the obtained sol at 160°C for 12 h to obtain a black xerogel; Step 6: Grind the obtained gel thoroughly and place it in a muffle furnace at 800℃ for solid phase reaction for 3h to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) TiO3; Step 7: Add 0.51 g of Bi(NO3)3·5H2O and 0.17 g of Na2WO4⋅2H2O to 50 ml of deionized water and stir to dissolve to obtain a white suspension; Step 8: 1g of (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2)TiO3 was added to the white suspension, and the mixed solution was added to a polytetrafluoroethylene-lined reactor, and a hydrothermal reaction was carried out at 120°C for 12 hours to obtain a composite photocatalytic material Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3. Example 3

[0026] A Bi2WO6 / (Bi2WO6) composite for carbon dioxide reduction using chemical bonds as electron transfer bridges 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) A method for preparing a TiO3 composite photocatalytic material, comprising the following steps: Step 1: Add 10 g of citric acid to 20 ml of deionized water and stir at 400 rpm for 1 h to fully dissolve to obtain a citric acid solution; Step 2: Add 25% ammonia water to the citric acid solution and adjust the pH to 8 to obtain an ammonium citrate solution; Step 3: Add 10 ml of tetrabutyl titanate and 10 ml of acetylacetone to the ammonium citrate solution and stir at 60°C for 5 h to obtain a light yellow double-layer solution, and separate a transparent titanium citrate solution; Step 4: Add 2.84 g of Bi(NO3)3·5H2O, 0.50 g of NaNO3, 0.59 g of KNO3, 0.96 g of Ca(NO3)2, and 2.61 g of Sm(NO3)3·6H2O to the titanium citrate solution, stir at 100°C for 5 h, and dehydrate to form a sol; Step 5: Heat the obtained sol at 160°C for 10 h to obtain a black xerogel; Step 6: Grind the obtained gel thoroughly and place it in a muffle furnace at 600℃ for solid phase reaction for 2h to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) TiO3; Step 7: Add 0.64 g of Bi(NO3)3·5H2O and 0.22 g of Na2WO4⋅2H2O to 50 ml of deionized water and stir to dissolve to obtain a white suspension; Step 8: 1g of (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2)TiO3 was added to the white suspension, and the mixed solution was added to a polytetrafluoroethylene-lined reactor, and a hydrothermal reaction was carried out at 120 ° C for 12 h to obtain a composite photocatalytic material Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3. Example 4

[0027] A Bi2WO6 / (Bi2WO6) composite for carbon dioxide reduction using chemical bonds as electron transfer bridges 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) A method for preparing a TiO3 composite photocatalytic material, comprising the following steps: Step 1: Add 10 g of citric acid to 25 ml of deionized water and stir at 400 rpm for 1 h to fully dissolve to obtain a citric acid solution; Step 2: Add 10% ammonia water to the citric acid solution and adjust the pH to 8 to obtain an ammonium citrate solution; Step 3: Add 10 ml of tetrabutyl titanate and 10 ml of acetylacetone to the ammonium citrate solution and stir at 75°C for 8 h to obtain a light yellow double-layer solution, and separate a transparent titanium citrate solution; Step 4: Add 2.84 g of Bi(NO3)3·5H2O, 0.50 g of NaNO3, 0.59 g of KNO3, 0.96 g of Ca(NO3)2, and 2.61 g of Sm(NO3)3·6H2O to the titanium citrate solution, stir at 90°C for 7 h, and dehydrate to form a sol; Step 5: Heat the obtained sol at 160°C for 11 h to obtain a black xerogel; Step 6: Grind the obtained gel thoroughly and place it in a muffle furnace at 1000℃ for solid phase reaction for 2h to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) TiO3; Step 7: Add 1.13 g of Bi(NO3)3·5H2O and 0.38 g of Na2WO4⋅2H2O to 50 ml of deionized water and stir to dissolve to obtain a white suspension; Step 8: 1g of (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm0.2 )TiO3 was added to the white suspension, and the mixed solution was added to a polytetrafluoroethylene-lined reactor, and a hydrothermal reaction was carried out at 120 ° C for 12 h to obtain a composite photocatalytic material Bi2WO6 / (Bi2WO6) with a theoretical proportion of 18%. 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3.

[0028] Comparative Example 1 Step 1: Add 1.13 g of Bi(NO3)3·5H2O and 0.38 g of Na2WO4⋅2H2O to 50 ml of deionized water and stir to dissolve to obtain a white suspension; Step 2: Add the white suspension into a polytetrafluoroethylene-lined reactor and perform a hydrothermal reaction at 120°C for 12 hours to obtain Bi2WO6.

[0029] Comparative Example 2 Step 1: Add 10 g of citric acid to 20 ml of deionized water and stir at 400 rpm for 1 h to fully dissolve to obtain a citric acid solution; Step 2: Add 25% ammonia water to the citric acid solution and adjust the pH to 8 to obtain an ammonium citrate solution; Step 3: Add 10 ml of tetrabutyl titanate and 10 ml of acetylacetone to the ammonium citrate solution and stir at 60°C for 5 h to obtain a light yellow double-layer solution, and separate a transparent titanium citrate solution; Step 4: Add 2.84 g of Bi(NO3)3·5H2O, 0.50 g of NaNO3, 0.59 g of KNO3, 0.96 g of Ca(NO3)2, and 2.61 g of Sm(NO3)3·6H2O to the titanium citrate solution, stir at 100 °C for 5 h, and dehydrate to form a sol; Step 5: Heat the obtained sol at 160 °C for 10 h to obtain a black xerogel; Step 6: Grind the obtained gel thoroughly and place it in a muffle furnace at 600℃ for solid phase reaction for 2 h to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) TiO3.

[0030] Comparative Example 3 Step 1: 0.2g of Bi2WO6 obtained in Comparative Example 1 and 0.44g of (Bi 0.2 Na 0.2 K 0.2 Ca0.2 Sm 0.2 )TiO3 is fully ground to obtain physically mixed (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3+Bi2WO6.

[0031] Structural characterization Figure 1 The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1, (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 material and Comparative Example 3 (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )XRD spectrum of TiO3+Bi2WO6. Figure 1 It can be seen that (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 is a typical characteristic peak of perovskite, and no second phase is observed, indicating the successful synthesis of high entropy perovskite. 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite material XRD spectrum observed that with the increase of Bi2WO6 content, the Bi2WO6 diffraction peak intensity also increased, indicating the successful formation of the composite material. 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )Comparing the XRD patterns of the physical mixture of TiO3 and Bi2WO6, all the diffraction peaks of Bi2WO6 are sharply weakened. This is because (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) Chemical bonds are formed between the TiO3 and Bi2WO6 surfaces, resulting in the formation of microcrystalline Bi2WO6 on the (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 surface growth.

[0032] Figure 2 The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1 and (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) SEM spectrum of TiO3 material. Figure 2 It can be seen that the morphology of Bi2WO6 in Comparative Example 1 is a flower-like structure, while that in Comparative Example 2 (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 is in the form of dispersed nanoparticles. In Examples 1 to 4, Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 SEM images show that Bi2WO6 nanosheets are uniformly distributed on (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 ) on the surface of TiO3 particles. 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )The epitaxial growth on the TiO3 substrate is mediated by interfacial interactions, which promote the formation of Ti-OW bridging bonds and prevent Bi2WO6 from forming its original flower-like structure, confirming the successful formation of the heterojunction.

[0033] Photocatalytic reduction of CO2 experiment The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1, high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) TiO3 material and the physical mixture obtained in Comparative Example 3 (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) The performance test of photocatalytic reduction of carbon dioxide by TiO3+Bi2WO6 was conducted. The performance test of photocatalytic reduction of carbon dioxide was evaluated in a system consisting of a Labsolar-6A trace gas analyzer from Beijing Bofeilai Technology Co., Ltd. and a gas chromatograph GC9790PLUS from Zhejiang Fuli Analytical Instrument Co., Ltd. The specific process is as follows: 20 mg of the prepared catalyst was added to 1 mL of ethanol without adding any sacrificial agent or photosensitizer, and ultrasonic dispersion was performed for 10 minutes until the catalyst was evenly dispersed in the ethanol. The obtained suspension was then evenly added dropwise to a 20 cm 2 The quartz filter was then placed on a circular quartz filter and dried in a 60°C oven to form a uniform film. The quartz filter was then transferred to a 100ml glass reactor with an optical quartz window on top. This was tightly connected to a Labsolar-6A device and the entire system was evacuated. 99.995% pure carbon dioxide was then introduced into the system until the vacuum reading reached 80.0 kPa. The system was then evacuated again, and this process was repeated three times. After the third injection of carbon dioxide to 80 kPa, 100 μL of Mill-Q water was introduced into the reactor. The reaction was allowed to stand for 30 minutes to allow the carbon dioxide to adsorb onto the catalytic surface. The experiment was then conducted using a Xe lamp (PLS-SXE300+ / UV) light source. The products were analyzed using a GC9790PLUS gas chromatograph. The GC carrier gas was Ar, the detector was a hydrogen ion flame (FID), the inlet temperature was set at 200°C, the column oven temperature was set at 60°C, and the detector temperature was set at 200°C.

[0034] Figure 3 The Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 composite photocatalytic material, Bi2WO6 material obtained in Comparative Example 1, high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm0.2) TiO3 and Comparative Example 3 obtained physically mixed (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2) Photocatalytic reduction of CO2 performance of TiO3+Bi2WO6. Under the experimental conditions, no other gaseous and liquid products were detected except CO, indicating that the synthesized catalyst can convert CO2 into CO with high selectivity. As can be seen from the figure, Bi2WO6 has the lowest photocatalytic activity, with a CO yield of only 4.87 μmol / g / h; while (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 CO production rate is 5.64 μmol / g / h; (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )After TiO3 and Bi2WO6 are physically mixed, (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3+Bi2WO6 slightly improved the CO yield to 8.15 μmol / g / h; 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 and Bi2WO6 composite, Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 The photocatalytic activity of the TiO3 composite material was significantly improved, and it first increased and then decreased with the increase of Bi2WO6 content. When Bi2WO6 accounted for 11%, the photocatalytic activity was the highest, and the CO yield could reach 35.8 μmol / g / h, which was about 7.35 times that of Bi2WO6. 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )6.35 times that of TiO3.

[0035] The above description is only for better explanation of the embodiments of the present invention and is not intended to limit the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are intended to be within the scope of the present invention.

Claims

1. A high entropy perovskite composite photocatalytic material for carbon dioxide reduction, characterized in that: It is composed of (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )A material with an S-type heterostructure composed of TiO3 and Bi2WO6.

2. The high entropy perovskite composite photocatalytic material according to claim 1, characterized in that: Said (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )The molar ratio of TiO3 and Bi2WO6 is 50:10~1.

3. The method for preparing the high entropy perovskite composite photocatalytic material according to claim 1 or 2, characterized in that: The following steps are involved: Step 1: dissolving citric acid in deionized water to obtain a citric acid solution; Step 2: Adding aqueous ammonia to the citric acid solution and adjusting the pH to obtain an ammonium citrate solution; Step 3: adding tetrabutyl titanate and acetylacetone to the ammonium citrate solution, stirring, and separating to obtain a titanium citrate solution; Step 4: Add Bi(NO3)3·5H2O, NaNO3, KNO3, Ca(NO3)2, and Sm(NO3)3·6H2O to the titanium citrate solution, stir, and dehydrate to form a sol; Step 5: heating the obtained sol to obtain a gel; Step 6: The obtained gel is subjected to solid phase reaction to obtain high entropy perovskite (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3; Step 7: Add Bi(NO3)3·5H2O and Na2WO4⋅2H2O to deionized water and stir to dissolve to obtain a white suspension; Step 8: 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3 was added to the white suspension for hydrothermal reaction to obtain Bi2WO6 / (Bi 0.2 Na 0.2 K 0.2 Ca 0.2 Sm 0.2 )TiO3, which is the high entropy perovskite composite photocatalytic material.

4. The method for preparing a high entropy perovskite composite photocatalytic material according to claim 3, characterized in that: In step 1, the mass ratio of citric acid to deionized water is 1:1-4; in step 2, the concentration of ammonia water is 10-28%, and the pH is adjusted to 8.

5. The method for preparing a high entropy perovskite composite photocatalytic material according to claim 3, characterized in that: In step 3, the volume ratio of tetrabutyl titanate to acetylacetone is 1:1; the stirring temperature is 60-80° C., and the stirring time is 5-8 hours.

6. The method for preparing a high entropy perovskite composite photocatalytic material according to claim 3, characterized in that: In step 4, the molar ratio of Bi(NO3)3·5H2O, NaNO3, KNO3, Ca(NO3)2, Sm(NO3)3·6H2O and titanium citrate is 0.2:0.2:0.2:0.2:0.2:1; the stirring temperature is 80-100°C and the time is 5-8h.

7. The method for preparing a high entropy perovskite composite photocatalytic material according to claim 3, characterized in that: The heating temperature in step 5 is 160° C. and the heating time is 10 to 12 hours; the solid phase reaction temperature in step 6 is 600 to 1000° C. and the heating time is 2 to 4 hours.

8. The method for preparing a high entropy perovskite composite photocatalytic material according to claim 3, characterized in that: In step 7, the molar ratio of Bi(NO3)3·5H2O and Na2WO4·2H2O is 1-2:1, and the stirring time is 1-2 hours.

9. The method for preparing a high entropy perovskite composite photocatalytic material according to claim 3, characterized in that: The temperature of the hydrothermal reaction in step 8 is 120° C. and the time is 12 to 14 hours.

10. Use of the high entropy perovskite composite photocatalytic material according to claim 1 or 2 in photocatalytic carbon dioxide reduction.

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