Efficient hydrogen evolution with ZnO/SrTiO3 S-scheme heterojunction photocatalyst sensitized by Eosin Y

Developing efficient, stable, and cheap photocatalysts for H2 production has aroused great interest among researchers. Herein, noble-metal-free ZnO/SrTiO3 composite photocatalysts have been successfully prepared by hydrothermal method. X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffusion spectroscopy, and photoluminescence spectroscopy are used to characterize the obtained samples. The photocatalytic water splitting for H2 production by ZnO/SrTiO3 has been studied under simulated sunlight irradiation by using triethanolamine as a sacrificial agent and Eosin Y (EY) dye as a sensitizer. The orthogonal experiments are designed to optimize the photocatalytic reaction conditions for practical purposes. The influencing extents and trends of the factors have been investigated, including the catalyst composition and dosage, pH value of the solution, triethanolamine, and EY addition. Under the optimum conditions, the H2 production rate with ZnO/SrTiO3 is up to 16006.12 μmol g−1 h−1. The excellent performance of ZnO/SrTiO3 is attributed to the formation of a step-scheme (S-scheme) heterojunction, which promotes the separation of photocarriers and reduces their recombination probability.