Visible-light-driven photocatalytic activity of mixed phase CdS-flakes

A mixed phase cadmium sulfide (CdS) thin films were prepared through chemical synthesis for studying the visible-light-driven photocatalytic activity for wastewater treatment. The wastewater that contains a considerable amount of refractory organic substances such as congo red (CR), methylene blue (MB) and indigo carmine (IC) dye solutions were degraded under visible-light irradiation using the CdS thin films. Structural studies of the CdS photocatalyst indicated good crystallinity, showing mixed phases of the hexagonal and cubic structure. Morphological studies suggested a flake-like structure that is uniformly distributed over the entire surface of the substrate. Such morphology induces porosity, which helps for intercalating the organic dyes. The optical band-gap energy of film sample was found to be 2.35 eV, which helped for high photocatalytic activity in the degradation of the non-biodegradable CR dye under visible-light irradiations as compared to IC and MB dyes.