Single-Atom Pt Loaded Zinc Vacancies ZnO–ZnS Induced Type-V Electron Transport for Efficiency Photocatalytic H₂ Evolution

Semiconductor supported noble metal nanoparticles are widely used in H₂ evolution. Due to the high cost and low catalytic efficiency of noble metals, single-atom catalysts (SACs) are considered as very potential materials to overcome these shortcomings. Herein, the construction of the ZnO–ZnS heterojunction with an excess amount of Zn vacancies promotes the separation of charge carriers and improves the utilization of electrons. Meanwhile, the zinc vacancies on ZnS provide effective anchor sites for Pt atoms, which is beneficial to obtain highly dispersed single Pt atoms catalyst (ZOS-SAPt). Due to the formation of an intermediate energy level by zinc vacancies, the introduction of Pt single atoms promotes the novel type-V electron transport from the conduction band of ZnO to the intermediate energy level and then to the Pt atom. The type-V electron transport not only retains the high reduction potential of photogenerated electrons, but also avoids the loss of carriers. The resultant ZOS-SAPt shows outstanding photocatalytic performance for H₂ evolution under simulated sunlight, reaching 9.6 mmol g⁻¹ h⁻¹, which is 201 times that of ZnO–ZnS. These results provide important information for further development of photocatalysts.