Strain-induced band gap modulation in Type-II CdO/AlSe heterostructure for enhanced photocatalytic water splitting

This study investigated the CdO/AlSe heterostructure constructed by stacking CdO and AlSe, focusing on its stability, electronic structure, optical properties, and photocatalytic performance using first-principles calculations. The thermodynamic stability was confirmed through phonon spectrum analysis. The band structure, calculated using the HSE06/PBE method, revealed that the band gap of the CdO/AlSe heterostructure decreases compared to its individual components. Charge density, work function, and differential charge density analyses demonstrated that the CdO/AlSe heterostructure forms a type II heterojunction, where the internal electric field facilitates effective electron-hole pair separation. The band edge potential analysis indicated that the heterostructure adjusts the band edge positions of CdO and AlSe to enable photocatalytic reactions. Strain engineering was found to broaden the light absorption range, enhancing photocatalytic efficiency. Furthermore, the heterostructure showed excellent hydrogen evolution and oxygen evolution efficiency, confirming its potential as a highly effective photocatalyst for water-splitting applications.