Dipole polarization-driven spatial charge separation in defective zinc cadmium sulfoselenide for boosting photocatalytic hydrogen evolution

Abstract

The industrial interest of ZnCdS as the photocatalytic media for hydrogen evolution reaction (HER) is severely hindered by its sluggish interfacial charge transfer, limited active sites, and serious photocorrosions. Herein, to catalyze more efficient and robust HER, a series of Se-doped ZnCdS with sulfur vacancies (denoted as Se/V-ZnCdS) are ingeniously designed and facilely synthesized. Experimental and theoretical studies reveal that by inducing dipole polarization through defect engineering synergistic elemental doping, spontaneous polarization field is generated in the bulk phase of ZnCdS, which together with elevated Fermi level renders the Se/V-ZnCdS with desirable spatial charge separation and transfer. Thus, the optimal 0.6 %Se/V-ZnCdS exhibits the outstanding performance of 85.3 mmol·g·h and excellent stability up to 24 h. This work highlights the high efficiency of dipole polarization realized by vacancy synergistic atomic doping in optimizing HER kinetics, and provides a new pathway to develop robust photocatalysts based on metal sulfoselenide for water-splitting reactions.