Insights into the in-built Tb4+/Tb3+ redox centers for boosted hydroxyl radical yield and superior separation of charge carriers by investigating Tb2O3/g-C3N4 composite photocatalysts

(1) Background Recently, the issue of environmental pollution by wastewater containing dye molecules attracted researcher's attention. It is urgent that seeking high efficiency visible-light driven photocatalyst leads to mitigating environmental contamination. (2) Methods In this work, the novel Tb2O3/g-C3N4 composite photocatalysts have been successfully synthesized, and the enhanced photocatalytic performance has been thoroughly discussed based on the fully characterization. The X-ray diffraction and scanning electron microscopy exhibited crystalline phases and morphologies of obtained samples. The chemical states and composition of composite photocatalysts were characterized by the X-ray photoelectron spectrometer. The photoluminescence and photocurrent results proved that Tb2O3/g-C3N4 composite samples possessed higher separation efficiency than that of pure C3N4. The decomposition of organic contaminant and cycle experiment demonstrated that 0.8%Tb2O3/g-C3N4 composite photocatalyst possessed the best photo-degradation performance and had a good chemical stability. The trapping experiment illustrated that the significantly elevated photocatalytic performance could attribute to the loading of Tb2O3. (3) Significant findings The in-built redox centers of Tb4+/Tb3+ efficiently promoted the utilization of photo-generated electrons and proliferated the hydroxyl radical. Simultaneously, the mechanism of enhanced photocatalytic performance of obtained composite samples was proposed. This work provides a promising strategy to design novel visible-light-driven photocatalysts and further improve the photocatalysis mechanism survey.