Improving visible-light photocatalytic activity for hydrogen evolution over ZnIn2S4: A case study of alkaline-earth metal doping

A series of alkaline-earth metal doped ZnIn2S4 photocatalysts were prepared by the microwave-assisted hydrothermal method, and characterized using various analysis techniques, such as XRD, Raman, UV–vis spectra, photoluminescence spectra and SEM. The successful incorporation of Ca, Sr and Ba into the lattices of ZnIn2S4 was proved by Raman spectra. Photocatalytic results demonstrated that Ca doping could greatly enhance the activity of ZnIn2S4, with about two times higher than undoped ZnIn2S4, while Sr and Ba doping could not. The varied photocatalytic activities of doped ZnIn2S4 as a function of alkaline-earth metals as dopants were discussed on the basis of the sophisticated photoluminescence process.

► Ca-, Sr- and Ba-doped ZnIn2S4 were synthesized by a microwave-assisted hydrothermal method.
► Ca doping could greatly enhance the activity of ZnIn2S4 as two times higher than undoped ZnIn2S4.
► Activities of doped ZnIn2S4 were related to the sophisticated photoluminescence process.