Spin polarized graphene monolayer of van der Waals heterojunction for photocatalytic H2O overall splitting

Abstract

Graphene has long been considered to only transfer photo-generated electrons for H2 production in photocatalytic H2O splitting, however this “common sense” is quite different in our research. Herein, spin polarized graphene monolayer-based van der Waals heterostructure was constructed by chemical vapor deposition on two-dimensional MoS2. Theoretical and experimental results confirm that photogenerated e- and h+ are spatially separated and directionally transferred from MoS2 to the opposite regions of monolayer graphene to form “electric field” via. the van der Waals heterojunction under the spin polarized monolayer-graphene-induced polarization promotion, thus H2 and O2 generation can be simultaneously realized in the “electric field” under visible-light irradiation. In this case, photocatalytic H2O splitting has been transformed into a process similar to electrocatalytic H2O decomposition, as revealed by the mechanism calculation. This result updates the mechanism of photogenerated charge carrier transfer and photocatalysis over graphene-based photocatalysts.