Van der Waals Heterostructures Based on Porous Graphene for Photocatalytic Water Splitting

Hydrogen fuel produced from photocatalytic water splitting has been considered as a kind of clean energy source and has received extensive attention. Here, we design porous graphene (PG)-based heterostructures as photocatalysts by stacking blue phosphorus (BP) or transition metal dichalcogenides on PG using first-principles calculations and find that the heterostructures PG/BP, PG/WS2, and PG/SMoSe are promising photocatalysts for water splitting. Designed heterostructures exhibit enhanced light absorption in the visible range compared to their monolayers and have appropriate band structures for water oxidation and reduction. Additionally, the band alignment of the type-II heterostructures and the establishment of weak polarized electric fields in the interfacial region of the heterostructures affect the spatial separation of photogenerated electrons and holes into different monolayers to participate in water splitting more effectively. This work provides a direction for rationally designing van der Waals heterostructures for photocatalytic water splitting.