All-solid-state Z-scheme heterostructures of 1T/2H-MoS2 nanosheets-coupled V doped hierarchical TiO2 spheres for enhanced photocatalytic activity

Abstract Highly efficient all-solid-state Z-scheme semiconductors are of great significance to the photocatalytic performance. Herein, we design and construct edge-rich bicrystalline 1T/2H-MoS2 nanosheets cocatalyst modified V-doped hierarchical TiO2 microspheres for the photocatalytic removal of oxytetracycline hydrochloride. In this catalyst system, the conductive 1T phase of MoS2 accelerates the charge-transfer kinetics and works as an electron mediator in a Z-scheme, while 2H phase of MoS2 and V-TiO2 are the photosensitizer and reactant adsorbed sites, respectively. The optimized VTM-5% heterojunction possesses superior degradation efficiency than that of bare components, which is ascribed to the enhanced light-harvesting capacity, populated exposed active sites, rapid photogenerated charge transfer, and excellent affinity to reactant molecules. Moreover, a built-in electric field forms via an intensive electronic interaction of positively charged V-TiO2 and negatively charged 1T/2H-MoS2, as confirmed by density functional theory (DFT) calculation. This study provides new insights into the rational design of noble-metal-free cocatalyst based Z-scheme photocatalysts towards environmental remediation.