Design of a solar light-responsive metal oxide/CdS/SrTiO3 catalyst with enhanced charge separation for hydrogen evolution

A cadmium sulfide/strontium titanate (CdS/SrTiO3) composite with excellent charge separation efficiency was successfully developed by a simple precipitation process. The small band gap of CdS and the redox potential difference between CdS and SrTiO3 extended the solar light absorption range and improved the photo-generated charge separation, resulting in enhanced photocatalytic hydrogen evolution efficiency under solar irradiation. The ultraviolet-visible and photoluminescence analysis results indicated that the CdS/SrTiO3 composite possessed optimal synergistic effect for charge separation and solar light absorption when the coupling ratio of SrTiO3 was controlled at 3 wt%. Based on the improved charge separation of the CdS/SrTiO3(3), the CdS/SrTiO3(3) could exhibit significantly increased hydrogen evolution efficiency after coating with a small amount of PtO or CuO. The optimal photocatalytic hydrogen evolution efficiency was achieved when the surface of CdS/SrTiO3(3) was coated with 0.2 wt% of PtO; the hydrogen evolution rate of 0.2PtO/CdS/SrTiO3(3) was about 6 times higher than that of CdS, 4 times higher than that of CdS/SrTiO3(3), and 2.5 times higher than that of 0.3CuO/CdS/SrTiO3(3). (C) 2017 Elsevier Ltd. All rights reserved.