Electronic and optical properties of MoS2/α-Fe2O3(0001) heterostructures: a first-principles investigation

Abstract

Experimentally, MoS₂/α-Fe₂O₃ composites have exhibited excellent photocatalytic activity in photoelectrochemical tests. However, the micromechanism of their improved photocatalytic efficiency is not clear. In this research, we use MoS₂/α-Fe₂O₃(0001) heterostructures as a case to study the effects of interfacial atomic structure, electronic structure, and optical properties on the enhanced photocatalytic performance. Our results show that the MoS₂/Fe–Fe–O₃–R heterostructure is the most promising one in improving the photocatalytic performance. First, there is a strong coupling between the MoS₂ film and Fe–Fe–O₃–R surface, which could provide the channel for photo-generated carrier transfer. Moreover, the increase of carrier concentration in the MoS₂/Fe–Fe–O₃–R system can be predicted according to the emergence of occupied electronic states below the conduction band edge (CBE) and the enhancement of the Fermi level. Additionally, the MoS₂/Fe–Fe–O₃–R heterostructure can exhibit better optical absorption in the visible light range. In summary, these electronic features may shed light on the experimental phenomenon, and be helpful in further improving the photocatalytic performance of MoS₂/α-Fe₂O₃ composites.