Modulating the doping state of transition metal ions in ZnS for enhanced photocatalytic activity.

Transition metal ions (M = Ag + , Cu 2+ , Co 2+ , and Cr 3+ ) are surface or homogeneously doped into ZnS via facile cation-exchange reaction, and while Ag + and Cu 2+ doping does not induce sulphur vacancies (V s ) or zinc vacancies (V Zn ), Co 2+ and Cr 3+ doping induces V s . The surface doped catalysts exhibit greatly higher activity than the ZnS and homogenous doped catalysts for H 2 evolution and CO 2 reduction. The important role of the doping state on affecting the photo-absorption, carrier separation efficiency, and photoreaction kinetics has been systemically investigated and proposed. This work sheds light on the future design and fabrication of high-performance photocatalysts by element doping.