Spatiotemporally Synchronous Oxygen Self‐Supply and Reactive Oxygen Species Production on Z‐Scheme Heterostructures for Hypoxic Tumor Therapy

Abstract Photodynamic therapy (PDT) efficacy has been severely limited by oxygen (O 2 ) deficiency in tumors and the electron–hole separation inefficiency in photosensitizers, especially the long‐range diffusion of O 2 toward photosensitizers during the PDT process. Herein, novel bismuth sulfide (Bi 2 S 3 )@bismuth (Bi) Z‐scheme heterostructured nanorods (NRs) are designed to realize the spatiotemporally synchronous O 2 self‐supply and production of reactive oxygen species for hypoxic tumor therapy. Both narrow‐bandgap Bi 2 S 3 and Bi components can be excited by a near‐infrared laser to generate abundant electrons and holes. The Z‐scheme heterostructure endows Bi 2 S 3 @Bi NRs with an efficient electron–hole separation ability and potent redox potentials, where the hole on the valence band of Bi 2 S 3 can react with water to supply O 2 for the electron on the conduction band of Bi to produce reactive oxygen species. The Bi 2 S 3 @Bi NRs overcome the major obstacles of conventional photosensitizers during the PDT process and exhibit a promising phototherapeutic effect, supplying a new strategy for hypoxic tumor elimination.