Exploring Different Photocatalytic Behaviors Of Cdxzn1-Xseys1-Y Gradient-Alloyed Quantum Dots Via Composition Regulation

Gradient-alloyed quantum dots (QDs) are new and interesting photocatalysts for efficient solar-to-chemical energy conversion to solve increasing energy and environmental problems. Nevertheless, few studies have been devoted to exploring structure-property relationships of gradient-alloyed QDs via the composition regulation. Herein we offer band-engineered gradient-alloyed QDs CdxZn1-xSeyS1-y prepared by stoichiometry control over the composition manipulation and has a funnel-shaped energy level. The effect of band structure on the photocatalytic performance of CdxZn1-xSeyS1-y QDs demonstrated that the regulation of light-harvesting range, charge carrier separation ability and redox reactivity can be achieved by composition and size adjustments. The results show that red QDs have the best electron/hole separation ability and widest photon capturing scope, while blue QDs possess the highest redox reactivity, realizing the contaminant degradation and CO2 reduction, simultaneously, with a high apparent rate constant k(app) of 0.4237 min(-1). Moreover, green QDs could be employed as a well-luminescent material owing to the fast electron-hole recombination rate. The mechanistic investigations reveal that different activities are dependent on a combination of two factors, that are ion migration-induced conversion of electron configuration and size-induced band bending. The understanding obtained in the present study is valuable for on-demand designing the unique properties of gradient-alloyed QDs.