Preparation And Photocatalytic Performance Of MXene/Sulfide Semiconductor Composites

Semiconductor photolysis of water to produce hydrogen is considered as a promising technology to generate clean and sustainable energy.Sulfides have been widely studied because of their unique photoelectric and catalytic properties.However,as a photocatalytic material,sulfides often undergo photocorrosion and have poor stability.In addition,the charge carriers of most sulfide photocatalysts have poor mobility and are prone to defects in their structures,which greatly limit their large-scale application.MXene is a kind of new 2D material with strong light absorption ability and high carrier mobility,which is often used in photocatalysis.In this paper,Ti₃C₂in MXene was selected as the research object to prepare binary Ti₃C₂/Zn In₂S₄and ternary Ti₃C₂/Ti O₂-Cd S photocatalytic composites.Multiple characterization methods were used to analyze the composition,and the performance and mechanism of the material's photodegradation of water to hydrogen were studied.The research content mainly includes the following parts:(1)The binary Ti₃C₂/Zn In₂S₄composite was obtained by one-step hydrothermal method.The two-dimensional Zn In₂S₄nanosheets grew on the layered structure of Ti₃C₂,and the specific surface area of the pure Zn In₂S₄was increased.When the mass ratio of Ti₃C₂was 5%(ZIST-5),the photocatalytic activity reached 2.6mmol·g^-1·h^-1,which was 2.2 times higher than that of pure Zn In₂S₄,and showed good photocatalytic stability.(2)Using dimethyl sulfoxide(DMSO)as solvent and sulfur source,ternary Ti₃C₂/Ti O₂-Cd S(TTCS)composites were prepared by solvothermal method through self-sacrificing Ti₃C₂.In the process of material formation,Ti O₂is grown in situ on Ti₃C₂lamellar structure,while Cd S is grown on Ti₃C₂and TiO₂in the form of quantum dots.When the mass ratio of Cd S was 50%(TTCS-50),the photocatalytic activity was the best(2.6mmol·g^-1·h^-1),which was 1.7 times higher than that of pure Cd S.In these two systems,Ti₃C₂acts as a co-catalyst in the composite material,which significantly improves the photocatalytic activity of Zn In₂S₄and Cd S.The addition of Ti₃C₂greatly enhances the charge carrier migration ability of the sulfide semiconductor,and avoids the excessive recombination rate of photogenerated charge.