Enhanced Visible-Light Hydrogen-Production Activity of Copper-Modified ZnxCd1−xS

Copper modification is an efficient way to enhance the photocatalytic activity of ZnS‐based materials; however, the mechanisms of Cu2+ surface and bulk modifications for improving the activity are quite different. In this work, two different synthetic pathways were devised to prepare surface and bulk Cu2+‐modified ZnxCd1−xS photocatalysts through cation‐exchange and coprecipitation methods, respectively. Different Cu2+ modifications brought different effects on the phase structure, morphology, surface area, optical property, as well as the photocatalytic H2‐production activity of the final products. The optimized Cu2+‐surface‐modified ZnxCd1−xS photocatalyst has a high H2‐production rate of 4638.5 μmol h−1 g−1 and an apparent quantum efficiency of 20.9 % at 420 nm, exceeding that of Cu2+‐bulk‐modified catalyst at the same copper content. Cu2+ surface modification not only brings a new electron‐transferring pathway (interfacial charge transfer), but also produces new surface active sites for H2 evolution, reducing the recombination rate of photogenerated charge carriers. Surface modification: Two different synthetic pathways are devised to prepare surface and bulk Cu2+‐modified ZnxCd1−xS through cation‐exchange and coprecipitation methods, respectively. Cu2+ surface modification can provide a new electron‐transferring pathway (interfacial charge transfer) and also form new surface active sites for H2 evolution, resulting in enhanced visible‐light H2‐production activity (see picture).