The g-C3N4/CdO heterojunction as an efficient photo-electron catalyst for hydrogen production

Abstract

The electronic, optical, and photo-electro catalytic properties of the g-C3N4/CdO(CGN/CdO) heterojunction are studied by Density Functional Theory (DFT) calculations. The CGN/CdO heterojunction has a staggered band structure and indirect bandgap (1.976 eV), following the S-scheme mechanism. The absorption spectra of the heterojunction are substantially red-shifted and the absorption coefficients are significantly higher relative to the intrinsic g-C3N4(GCN) and intrinsic CdO. In addition, the power conversion efficiency (PCE) is 14.21 %. The photo-catalytic water decomposition can occur at pH = 0–14. The ηSTH of the GCN/CdO heterojunction is up to 31.82 %, and it is modulated to 36.14 % under −4 % biaxial strain modulation. The low over-potential of the Oxygen evolution reaction (OER) for the heterojunction is 0.905 V obtained at the GCN layer, and that of the Hydrogen evolution reaction (HER) is −0.498 V occurred at the CdO layer. These findings suggest that the GCN/CdO heterojunction has an efficient photo-electro catalytic potential for hydrogen production.