Computational analysis of the enhancement of photoelectrolysis using transition metal dichalcogenide heterostructures

Abstract

Abstract Finding a material with all the desired properties for a photocatalytic water splitter is a challenge yet to be overcome, requiring both a surface with ideal energetics for all steps in the hydrogen and oxygen evolution reactions (HER and OER) and a bulk band gap large enough to mediate said steps. We have instead examined separating these challenges by investigating the energetic properties of two-dimensional transition metal dichalcogenides (TMDCs) that could be used as a surface coating to a material with a large enough bulk band gap. First we investigated the energetics of monolayer MoS2 and PdSe2 using density functional theory and then investigated how these energetics changed when they were combined into a heterostructure. Our results show that the surface properties were practically ( < 0.2 eV) unchanged when combined and the MoS2 layer aligns well with the OER and HER. This work highlights the potential of TMDC monolayers as surface coatings for bulk materials that have sufficient band gaps for photocatalytic applications.