Thermal-assisted photocatalytic H2 production over sulfur vacancy-rich Co0.85Se/Mn0.3Cd0.7S nanorods under visible light

Abstract Defect engineering, heterojunction construction and photo–thermal synergy are efficient means to improve photocatalytic performance. Herein, we present Co0.85Se nanoparticles in-situ grown on sulfur vacancy-rich MnxCd1−xS nanorods. The as-obtained Co0.85Se/Mn0.3Cd0.7S heterojunctions achieved H2-production rate of 46.7 mmol/h/g at 5 ℃, which is 14 times higher than sulfur vacancy-poor Mn0.3Cd0.7S and better than 1 wt% Pt/Mn0.3Cd0.7S. Sulfur vacancies, nonstoichiometric Co0.85Se and Co0.85Se/MnxCd1−xS heterojunctions provide more active sites, harvest light and speed up charge carriers transfer for photocatalytic process. Moreover, elevating reaction temperature can decrease charge-transfer resistance, promote the kinetics for reducing H2O to H2, and thus accelerate H2-generation rate (up to 79.7 mmol/h/g at 25 ℃). The apparent quantum yield increases from 29.3% to 37.0% when the reaction temperature rises from 5 to 25 ℃. This work proposes a promising strategy for the application of sulfur vacancy and nonstoichiometric metal-selenide cocatalyst in thermo-assisted photocatalysis.