Photostable hollow core-shell ZnSe@PDA-7 type-II heterojunction with built-in electric field for efficient photocatalytic generation of H₂O₂

Various strategies have been developed to prevent electron-hole recombination and photocorrosion in sulfur-based semiconductors, improving catalyst efficiency and enabling high-activity, stable photocatalytic H₂O₂ generation. In this study, we construct a hollow core-shell catalyst by tightly coating hollow ZnSe microspheres with an organic semiconductor polydopamine (PDA) via a self-polymerization method, effectively reduces the impact of photocorrosion on ZnSe. DFT calculations confirmed the formation of a built-in electric field at the ZnSe/PDA interface, which, under its influence, promotes the creation of a type-II heterojunction favorable for photocatalytic H₂O₂ generation. The built-in electric field and type-II heterojunction enhance charge carrier transfer and separation. The PDA coating also improves O₂ adsorption and light utilization of ZnSe, further enhancing H₂O₂ photocatalytic performance. Results show that ZnSe@PDA-7, with optimal PDA loading, achieves an H₂O₂ generation rate of 1978.5 μmol g^-1 h^-1 under visible light irradiation in pure water. This method of organic polymer coating on chalcogenide semiconductors effectively mitigates photocorrosion effects and improves charge carrier separation, offering a sustainable solution for clean energy synthesis.