Synergistic effect of doping-induced oxygen vacancies, in-built Tb4±/Tb3± redox centers and heterojunction on the photocatalytic activity of Sm- doped ZnO/Y-doped Tb2O3 for H2 evolution

The present work signifies the impact of doping-induced oxygen vacancies, the formation of heterojunction, and the role of Tb4+/Tb3+ redox centers on the photo-activity of Sm-ZnO/ Y-Tb2O3 composite. The generation of oxygen vacancies in the produced materials is explained by PL, FTIR, and XRD analyses as a result of distortion in the local framework of oxygen ions around Zn and Tb ions. Under simulated sunlight irradiation, the Sm-ZnO/Y-Tb2O3 catalyst demonstrates efficient photocatalytic activity, obtaining an apparent amount of 21,270 mol g -1 h-1, which is around 60 times greater than that obtained over ZnO. The Sm-ZnO/Y-Tb2O3 catalyst also manifests strong stability. The generation of oxygen vacancies, the effective role of Tb4+/Tb3+ redox centers, the design of hetero-junction, and high specific surface area are the responsible factors for the increased optical response, spatial separation, and fast transport of charge carriers and large density of catalytic sites to boost the H2 evolution performance. The present study can deepen the knowledge of the design and construction of novel heterosystems with strong photo -catalytic aptitudes. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.