Construction of Ag2S@CaTiO3 heterostructure photocatalysts for enhanced photocatalytic degradation of dyes

In this work, we have assembled Ag 2 S carbon quantum dots (CQDs) onto CaTiO 3 nanocuboids (NCs), aimed at creating Ag 2 S@CaTiO 3 composite photocatalysts with superior photocatalytic performances. Scanning/transmission electron microscopy observation confirms the uniform decoration of Ag 2 S CQDs (7–17 nm) on the surface of CaTiO 3 NCs with size of 0.8–1.1 μm in length and 0.3–0.5 μm in width. Photoluminescence, photocurrent response and electrochemical impedance spectroscopy investigations reveal that the Ag 2 S@CaTiO 3 composites manifest highly efficient separation of photoexcited electron/hole pairs. The photocatalytic degradation activity of the Ag 2 S@CaTiO 3 composites was assessed by the removal of rhodamine B from aqueous solution. It is demonstrated that the composites exhibit photocatalytic degradation performance much superior to that of bare Ag 2 S CQDs and CaTiO 3 NCs under ultraviolet irradiation. This can be explained as the result of efficient separation of photoexcited electron/hole pairs induced by the Z-scheme electron transfer. In addition, the composites also manifest enhanced visible-light photocatalytic performance when compared with bare CaTiO 3 NCs, implying that they can make the best use of the solar energy in the practical photocatalytic applications.