Prominent roles of Ni(OH) 2 deposited on ZnIn 2 S 4 microspheres in efficient charge separation and photocatalytic H 2 evolution.

In this work, Ni(OH) 2 -deposited ZnIn 2 S 4 microspheres (Ni(OH) 2 /ZnIn 2 S 4 ) were fabricated using a hydrothermal process, followed by a facile in situ precipitation method. It was demonstrated that the deposition of Ni(OH) 2 on ZnIn 2 S 4 effectively promotes the separation of charges photogenerated over ZnIn 2 S 4 , and significantly enhances photocatalytic H 2 evolution. The optimum rate of the photocatalytic H 2 evolution over the 6% Ni(OH) 2 /ZnIn 2 S 4 composite reaches 4.43 mmol g -1 h -1 , which is 21.1 times higher than that of the pure ZnIn 2 S 4 . Based on various characterization results and Au photo-deposition on the composite, it was proposed that the capture of the photogenerated holes by the deposited Ni(OH) 2 would be responsible for the efficient charge separation, which allows more photogenerated electrons to be left on the ZnIn 2 S 4 for the reduction of H + to H 2 with a higher rate.