Sunlight assisted degradation of a pollutant dye in water by a WO3@g-C3N4 nanocomposite catalyst

Abstract

A series of WO₃@g-C₃N₄ nanocomposites were synthesized and characterized by different physico-chemical techniques. The photocatalytic performance was investigated by degradation of Rhodamine B (100 ppm) in the presence of H₂O₂ under sunlight irradiation. The optimum loading of WO₃ for the best performance is 2 wt%, at which the WO₃@g-C₃N₄ nanocomposite exhibits the highest degradation efficiency of 99.5% under sunlight irradiation. The degradation with 2 wt% WO₃@g-C₃N₄ follows pseudo first order kinetics and the rate constant is almost 2.6 and 7.7 times higher than that of ‘neat’ g-C₃N₄ and WO₃. This WO₃@g-C₃N₄ showed good recyclability with 94.2% efficiency after the seventh cycle. The enhancement of the photocatalytic efficiency of as-synthesized WO₃@g-C₃N₄ nanocomposites may be due to the synergistic effect between WO₃ and g-C₃N₄, high separation and easy transfer of photo-excited charge carriers at the interface of nanocomposites and the high specific area of the nanocomposites. The finding suggests that the as-synthesized WO₃@g-C₃N₄ can exhibit high potential towards solar energy harvesting and environmental remediation.