| As a new approach in the field of catalysis,photothermal collaborative catalysis can improve the shortage of single photocatalytic thermal catalysis and realize the efficient utilization of solar energy.The design of an eff-icient and stable photothermal catalyst and the exploration of photothermal cooperative catalytic mechanism are the research frontier of this field.The bismuth oxychloride compounds Bi4MO8X(M-Nb,Ta;X-Cl,Br),as a new photocatalytic material,has the characteristics of wide optical absorption range,high optical carrier separation rate and catalytic stability.However,the photothermal response of Bi4MO8X is poor.How to activate Bi4MO8X to become an efficient photothermal catalyst for sunlight-heat conversion remains to be studied.In this paper,Bi4TaO8Cl was activated by constructing Z-scheme heterojunction and introducing oxygen vacancy,respectively study Bi4TaO8Cl/Wi8O49 Z-scheme heterojunction and oxygen vacancy Bi4TaO8Cl catalyst of CO2 photothermal reduction performance,providing a promising technical means for the design of efficient photothermal CO2 reduction catalyst.Specific research contents are as follows:(1)Photothermal reduction of CO2 catalysis of Bi4TaO8Cl/Wi8O49 Z-scheme.we prepared a new Z-scheme photocatalyst by using non-stoichiometric tungsten oxide plasma Wi8O49 loaded on the surface of Bi4TaO8Cl nanoplate,and studied for the first time the photothermal catalytic reduction of CO2 activity on Bi4TaO8Cl/Wi8O49 Z-scheme heterojunction.Compared with Bi4TaO8Cl,the reduction of CO2 by theZ-scheme heterojunction has increased the yield of CO by 1.92 times,in photothermal catalysis it was 167.29 times higher than pristine Bi4TaO8Cl under the conventional photocatalytic process at 298 K.Comprehensive analysis shows that photothermal catalysis not only reduces the activation energy of the reaction,increases the number of electrons on the catalyst surface involved in CO2 reduction,and improves the surface reaction rate,but also greatly promotes the Z-scheme behavior of electrons-holes at the interface of Bi4TaO8Cl/Wi8O49 heterostructure.It is worth noting that the Bi4TaO8Cl/Wi8O49 Z-scheme heterojunction extend thermal catalytic CO2 reduction under the dark state.That is,electrons stored in WigO49 in the dark state can be transferred by thermal activation to the conduction band of Bi4TaO8Cl to participate in CO2 reduction.In conclusion,the photothermal synergy can enhance the Z-scheme behavior of electron holes in Bi4TaO8Cl/Wi8O49 heterostructure,which inspires the design of efficient Z-scheme catalysts for solar fuel production.(2)Photothermal reduction of CO2 catalysis of oxygen vacancy Bi4TaO8Cl.Bi4TaO8Cl nanosheet with thickness of about 200 nm was synthesized by molten salt method,and then Bi4TaO8Cl nanosheet was treated with the advantages of high strength electric field and H free radical generated by high-pressure pulsed liquid discharge of solution plasma.After treatment,the original sample morphology was maintained to a great extent,the optical absorption band edge red shifted,the specific surface area increased,the catalytic active sites increased and the oxygen defect signal enhanced.Theoretical studies have shown that the(Bi2O2)2+layer on the(001)crystal surface exposed by Bi4TaO8Cl can generate oxygen vacancy in situ,which is not only conducive to charge separation,but also conducive to the adsorption and electronic activation of reactants on the surface,reducing reaction activation energy and improving CO2 reduction capacity.It was consistently observed that the photocatalytic and photothermal catalytic effects of Bi4TaO8Cl samples after treatment were enhanced,and the production of Bi4TaO8Cl samples from photothermal reduction of CO2 to CO increased by 16.5 times than that of Bi4TaO8Cl photo reduction of CO2.The photothermal cooperative catalysis was conducive to the secondary release of photogenerated electrons at the defects,and the utilization rate of photogenerated carriers was improved,so the photothermal efficiency was significantly improved. |
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