Revealing the role of surface elementary doping in photocatalysis

Abstract

Efficient photocatalysis requires the facilitation of the rate-determining step of semiconductor–cocatalyst interfacial electron transfer and catalysis of hole extraction, which are involved in the spatial separation of photogenerated charge carriers from the light absorber. We here demonstrate that interfacial transfer of electrons to the cocatalyst can be promoted by creating more surface sites for trap-assisted charge recombination. The sites formed by surface elementary doping can also modify the electronic states, which makes the potential for the oxidation half-reaction occurring on the semiconductor surface less positive. By these merits, the dilemma of sunlight-driven photocatalysis resulting from light-intensity-dependent photon utilization can be overcome after doping the visible-responsive CdS with manganese.