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

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.