Constructing of 3D flower-like MoS2/Bi4Ti3O12 p-n heterojunction for the enhancement of photocatalytic degradation of dyes

In this study, Bi4Ti3O12 nanosheets and flower-like MoS2 were synthesized by hydrothermal method and compounded into p-n heterojunctions with 2D–2D structure. The stable p-n heterojunctions exhibit excellent visible-light-driven catalytic activity through effective electron/hole (e-/h+) separation, which generates a built-in electric field between the two components, accelerates the separation efficiency of photogenerated charges between the materials, and reduces the photogenerated electron-hole complexation efficiency. The methylene blue (MB) was degraded under simulated sunlight conditions, and the removal efficiency of MB at an initial concentration of 10 mg/L could reach 91.1% within 270 min. HRTEM and microstructural study revealed microscopic close interaction between the two phases, which can shorten the transport path of photogenerated electron-hole pairs, and optical measurement studies show a significant improvement in visible light absorption and charge carrier separation due to the formation of heterojunctions. Free radical quenching experiments and electron paramagnetic resonance (EPR) showed that the main active substances are·OH and·O2-, and photogenerated h+ is also involved in the photocatalytic reaction process. The system also shows good degradation efficiency in different water matrices, five-cycle experiments, and good structural stability elucidate its potential application in degrading emerging pollutants for water purification.