Heterojunction nanoarchitectonics with SnS2/g-C3N4 S-scheme toward enhanced photooxidation and photoreduction

Abstract

Novel g-C3N4/SnS2 van der Waals heterojunctions were fabricated via SnS2 crystals embedded superior thin g-C3N4 nanosheets for efficient photocatalytic oxidation and reduction activities simultaneously. S-scheme charge migration path was confirmed through test and density functional theory (DFT) calculation. Two dimensional (2D)/2D interfaces, powerful internal electric field (IEF) and band bending effect together expedited charge transfer. Photocatalytic removal of organic pollutants and hydrogen evolution were employed to evaluate photocatalytic performance. Particularly, the g-C3N4/SnS2 heterojunctions exhibited excellent 2,4-dichlorophenol (2,4-DCP) photooxidation and Cr(VI) photoreduction activities at the same time. 85% of Cr(VI) and 94% of 2,4-DCP were removed in the mixed solution after visible light irradiation for 2 h (λ > 420 nm). The hydrogen evolution rate enhanced to ∼6.58 times of g-C3N4. DFT simulation matched with test for narrowed band gap and enhanced IEF (accelerating photogenerated carrier transfer). This work provided new insights for constructing S-scheme multifunctional g-C3N4-based photocatalyst.