First-principles perspective on the enhanced photocatalytic performance of the direct Z-scheme ZnO/β-AsP heterostructure for water splitting

Direct Z-scheme heterostructure-based catalysts are highly desirable for hydrogen generation through photocatalytic water splitting. In this work, a direct Z-scheme ZnO/β-AsP heterostructure is theoretically proposed, and its photocatalytic performance is investigated using the first-principles method. The synergistic effects of reduced bandgap, improved light absorption, enhanced carrier mobility, and lowered exciton binding energy in ZnO/β-AsP heterostructure contribute to its superior optoelectronic properties. The strong built-in electric field of ZnO/β-AsP heterostructure facilitates the spatial separation of photoexcited carriers, while its band edges straddle the redox potentials of water. The transfer of photoexcited carriers follows a Z-scheme pathway, enabling efficient carrier separation and robust redox capability. Furthermore, tensile strain engineering significantly optimizes the electronic structure of ZnO/β-AsP heterostructure, boosts light absorption, and fulfills the thermodynamic feasibility of overall water splitting. This theoretical study highlights ZnO/β-AsP heterostructure as a promising direct Z-scheme catalyst for solar-driven water splitting, providing valuable theoretical guidance for the design of high-performance direct Z-scheme photocatalysts.