Rationalizing and controlling the phase transformation of semi-metallic 1T′-phase and semi-conductive 2H-phase MoS2 as cocatalysts for photocatalytic hydrogen evolution

Abstract

In this study, we report that the 2D semi-metallic 1T′-MoS2 serves as co-catalyst in assisting 1T′-MoS2/g-C3N4 composites obtained via a one-pot hydrothermal technique for boosting photocatalytic H2 evolution, and the phase transformation from 1T′ to 2H is achieved via thermal treatment. The designed 1T′-MoS2/g-C3N4 composite exhibits significant enhancement than pure g-C3N4 and 2H-MoS2/g-C3N4. The 1T′-MoS2/g-C3N4 composite with optimum 20 wt% 1T′-MoS2 displays a significantly improved photocatalytic H2 production rate (4426 μmol·h−1·g−1), which is about 86.7 and 1.41 times of pure g-C3N4 and 20 wt%–2H-MoS2/g-C3N4 composite, along with excellent stability. Besides, the apparent quantum efficiency (AQE) of 1T′-MoS2/g-C3N4 composite (20 wt%) achieves 13.55%. 1T′-MoS2 co-catalysts not only serve as effective electron acceptors, but have the merits of the energetically more stable.