Z-Scheme Mo2C/MoS2/In2S3 dual-heterojunctions for the photocatalytic reduction of Cr(vi)

Abstract

The inferior separation efficiency of photo-induced carriers is still a major obstacle to the practical application of photocatalysts, whereas the spatial separation of reductive and oxidative components is expected to break through this bottleneck to promote charge separation and surface reaction kinetics. Herein, Mo₂C nanosheets were employed to prepare a Mo₂C/MoS₂/In₂S₃ dual-heterojunction (a p–n junction of MoS₂/In₂S₃ and a Schottky junction of Mo₂C/In₂S₃) by one-pot solvothermal synthesis. Theoretical and experimental results proved that Mo₂C acted as an electron transport “highway” and acceptor in Mo₂C/MoS₂/In₂S₃ dual-heterojunctions to expedite the spatial migration of electrons. Compared with In₂S₃ and MoS₂/In₂S₃, the optimized Mo₂C/MoS₂/In₂S₃ composite exhibited significantly improved photocatalytic property, with the Cr(VI) reduction efficiency reaching 99.1% in 90 min under visible light irradiation. This study demonstrates that Mo₂C may play a major role in an electron sink that can be used as a potential co-catalyst in multijunctional photocatalysts.