A first principles study of structural and optoelectronic properties and photocatalytic performance of GeC–MX2 (M = Mo and W; X = S and Se) van der Waals heterostructures

Abstract

Two-dimensional (2D) materials have received enormous attention as photocatalysts for hydrogen production to address the worldwide energy crisis. In this study, we employed first-principles computations to systematically investigate the structural, opto-electronic, and photocatalytic properties of novel GeC–MX₂ (M = Mo, W, X = S, Se) van der Waals (vdW) heterostructures for photocatalysis applications. Our results reveal that the GeC–MX₂ heterostructures can absorb visible light. The type-II band alignment in GeC-MoS₂ and GeC-WS₂ enables the photogenerated electron–hole pairs to be separated continuously. The electron transfer from the GeC monolayer to MX₂ monolayer leads to a large built-in electric field at the interface. This induced electric field is essential for preventing the recombination of photogenerated charges. Moreover, the band-edge locations suggest that GeC–MX₂ heterostructures can be utilized as a photocatalyst for water splitting. Finally, the opto-electronic properties of these novel GeC–MX₂ heterostructures facilitate their practical utilization in future photocatalysis applications.