A first-principles study on the CdS-Te van der Waals heterostructure for Photocatalytic Hydrogen Production

Two dimensional (2D) materials are showing advantageous electronic and optical properties compared to their bulk counterparts. Recently 2D heterostructures attracted much attention in catalysis. Here, we demonstrate novel chalcogen based 2D-2D heterostructure CdS-Te with improved efficiency for the water splitting hydrogen production. We analysed the structural, electronic and optical properties of this CdS-Te heterostructure using first principles DFT calculations. Compared with the pristine monolayers of Te and CdS, we noticed significant improvement in the solar visible light absorption, and charge transfer properties in the material after heterostructure construction. This is due to the electric field created at the interface of CdS and Te monolayers. To attain the favorable band alignment for the water redox reaction, we applied the biaxial strain and electric field on the CdS-Te heterostructure. The Gibbs free energy calculations also exhibit less energy barrier for the CdS-Te heterostructure. From the obtained results, it is observed that the applied biaxial strain followed by the heterostructure construction improved the photocatalytic water splitting capacity of the material proficiently.