Synthesis of SiO2-doped BiOX (X = Cl, Br) II-type heterojunctions and 2H-MoS2-doped SiO2@BiOX Z-scheme heterojunctions: A comparative study

Abstract

In this research, II-type SiO2@BiOX (X = Cl, Br) was synthesized by loading SiO2 microspheres onto 2D layered BiOX using a simple one-step hybrid solvothermal method. On this basis, the two-dimensional bismuth oxyhalide layer was modified by using 2H-MoS2 layer and compounded with SiO2 microspheres to form 2H-MoS2@SiO2@BiOX (X = Cl, Br) Z-scheme heterostructured photocatalysts. The energy band structure and photogenerated carrier transport mechanism of the composite photocatalysts were analyzed by various characterization methods, and the transport efficiency of photogenerated carriers of II-type heterojunction and Z-scheme heterojunction were compared. The differences in photocatalytic activities of II-type heterojunctions and Z-scheme heterojunctions were shown by microscopic mechanisms and macroscopic phenomena. The photocatalytic degradation experiments showed that the doping of 2H-MoS2 acted as a conducting medium in the p-BiOX/n-SiO2 heterostructure, which changed the photogenerated electron transfer and formed the Z-scheme heterojunction structure, thus promoting the photocatalytic activity. In this study, the structure of BiOX-based composite photocatalyst was optimized and constructed, and a new idea was provided for the design and construction of II-type heterojunction and Z-scheme heterojunction photocatalysts.