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 nanosheet 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 is 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 calculation. This study provides new insights into the rational design of noble metal-free cocatalyst-based Z-scheme photocatalysts toward environmental remediation.