Spontaneously enhanced visible-light-driven photocatalytic water splitting of type II PG/AlAs5 van der Waal heterostructure: A first-principles study

To solve the problem of energy scarcity and widespread environmental contamination, it is necessary to design green and low-cost photocatalysts for water splitting. In this paper, a new penta-graphene/AlAs5 (PG/AlAs5) van der Waals (vdW) heterostructure is proposed and its performance for photocatalytic hydrolysis is calculated using the first-principles method. The findings suggest that the PG/AlAs5 heterostructure belong to type-II indirect semiconductor, and the edge position and band gap width of this heterostructure satisfy the requests of redox reaction. Furthermore, the oxidation reaction (OER) on the AlAs5 side and the hydrogen evolution reaction (HER) on the PG side are thermodynamically spontaneous under different conditions. Surprisingly, the introduction of strain engineering has changed the position of the band edge and light absorption performance of PG/AlAs5 heterostructure, which is powerful for the performance of photocatalytic water splitting. The PG/AlAs5 vdW heterostructure exhibits well visible light absorption intensity without applying strain and biaxial strain of 2%. In conclusion, the findings suggest that the PG/AlAs5 vdW heterostructure is a prospecting catalyst for visible-light hydrolysis.