Heterostructured metal sulfide (ZnS–CuS–CdS) photocatalyst for high electron utilization in hydrogen production from solar water splitting

H2-production from solar water splitting attracts great attention due to its cleanness and renewable characteristics in converting solar energy into chemical energy. A sequential fabrication approach for metal sulfide photocatalysts consisting of three components (ZnS, CuS, and CdS) is designed in order to achieve efficient charge flows by introducing CuS and CdS on ZnS surfaces. ZnS particles are firstly synthesized as a base material through colloidal precipitation, and then the ZnS surfaces are sequentially modified by adding CuS (cation exchange reaction) and CdS (ionic reaction) precursors. For the final products (ZnS–CuS–CdS), atomic compositions are carefully analyzed. The ZnS–CuS–CdS composite photocatalyst reaches a maximum H2-production rate (837.6 μmol/g h) at Cu 0.81 wt% and Cd 14.7 wt% under the standard solar irradiation (1 kW/m2, AM 1.5 G) compared to the ZnS only case (13.5 μmol/g h). This highly enhanced photocatalytic activity is due to synergistic effects of heterostructured ZnS–CuS–CdS photocatalyst which can improve charge flow and light absorption. This study shows a great possibility of manufacturing multi-component metal sulfide systems for improving H2-production activity from solar water splitting.