Constructing Anatase TiO₂ Nanosheets with Exposed (001) Facets/Layered MoS₂ Two-Dimensional Nanojunctions for Enhanced Solar Hydrogen Generation

Abstract

Cocatalysts have been extensively used to accelerate the rate of hydrogen evolution in semiconductor-based photocatalytic systems, but the influence of interface state between semiconductor and cocatalyst has been rarely investigated. Here, we demonstrate a feasible strategy of two-dimensional (2D) nanojuctions to enhance solar hydrogen generation of the MoS 2 /TiO 2 system. Loading of 2D MoS 2 nanosheets on the surface of 2D anatase TiO 2 nanosheets with exposed (001) facets greatly increases the interfacial contact. At an optimal ratio of 0.50 wt % MoS 2, the 2D-2D MoS 2 /TiO 2 photocatalyst shows the highest H 2 evolution rate of 2145 μmol h –1 g –1, which is almost 36.4 times higher than that of pure TiO 2 nanosheets. The apparent quantum yield of hydrogen evolution system reaches 6.4% at 360 nm. More importantly, the 2D-2D MoS 2 /TiO 2 composite exhibits photocatalytic activity much higher than those of noble metal (such as Pt, Rh, Ru, Pd, and Au) loaded TiO 2 photocatalysts. The decisive factor in improving the photocatalytic H 2 production activity is an intimate and large contact interface between the light-harvesting semiconductor and cocatalyst. The effective charge transfer from TiO 2 to MoS 2 is demonstrated by the significant enhancement of photocurrent responses in 2D-2D MoS 2 /TiO 2 composite electrodes. This work creates new opportunities for designing and constructing highly efficient photocatalysts by interface engineering.