Cu2O/BiVO4 heterostructure controllably triggers radical and non-radical persulfate activation via light “on-off” for efficient organic contaminants degradation

Abstract

The regulation of peroxydisulfate (PDS) activation pathway is crucial for its practical application in complicated water matrix. In this work, we have developed a Cu2O/BiVO4 (Cu-BVO) heterostructure to achieve controlled triggering of both radical and non-radical PDS activation by dexterously utilizing light “on-off” for highly efficient degradation of organic contaminants. In dark condition, Cu-BVO serves as an electron donor to facilitate the cleavage of O-O bond in PDS via a radical pathway to generate •OH and •O2-. Upon light irradiation, Cu-BVO unexpectedly acts as an electron acceptor in the reversed electron flow to generate a metastable surface complex (Cu-BVO-PDS*) via non-radical pathway. Analysis of the kinetic behavior of the excited electrons and holes suggests that the directional migration of photo-excited charge carriers in Cu-BVO results in the electron-deficient region on the Cu2O surface, which provides an ideal platform for the generation of Cu-BVO-PDS*.