Enhancing photocatalytic activity for hydrogen production and pollutant degradation by modifying tetragonal ZrO₂ with monolayers slab surface of BiVO₄, Ag₃PO₄, SrTiO₃ and WO₃: A first-principles study

Semiconductor-based photocatalysis has received increasing attention in energy storage and environmental remediation process due to the abundant solar energy. For this purpose, heterostructures of ZrO₂ coupled with BiVO₄, Ag₃PO₄, SrTiO₃ and WO₃ monolayers are designed to examine their potential applications in hydrogen production and degradation of pollutants using density functional theory (DFT) + U method for the first time. The results revealed that the calculated band gaps of the heterostructures are reduced compared to the pure ZrO₂, which favour redshift absorption. A type-I band alignment is attained for the BiVO₄/ZrO₂, Ag₃PO₄/ZrO₂ and WO₃/ZrO₂ heterostructures. More importantly, a type-II staggered band alignment formed in the SrTiO₃/ZrO₂ heterostructure restrained the charge recombination rate of photoinduced charge carriers, as well as enhancing the photocatalytic activity. In particular, suitable band alignment of SrTiO₃/ZrO₂ with enough driving forces for charge carrier transfer show overall water splitting and degradation of pollutant in which SrTiO₃ acted as charge separation centre. Furthermore, h⁺, [Figure presented] and [Figure presented] radicals played a major role in the photocatalysis process of the SrTiO₃/ZrO₂ heterostructure. These results reveal that the ZrO₂ acts as an oxidation site so that better access of electron acceptor to the interface is a significant factor that improves the photocatalytic activity of SrTiO₃/ZrO₂ heterostructure towards H₂ evolution.