Sunlight-driven photocatalytic degradation of rhodamine B dye by Ag/FeWO4/g-C3N4 composites

Abstract

A wide range of processes have been adopted for environmental remediation; among them, photocatalysis appeared as an appealing strategy for degradation of organic pollutants. Heterogeneous photocatalysis efficiently dissociates the charge carriers and helps in reducing the rapid recombination rate of charge carriers resulting in enhanced photocatalytic degradation. A semiconductor photocatalyst graphitic carbon nitride (g-C3N4), when doped with metals or non-metals, showed increased degradation abilities. Hence, a ternary photocatalyst was synthesized by thermal condensation of urea coupled with ferric tungstate (FeWO4) and doped with a noble metal (Ag) resulting in visible light susceptive semiconductor photocatalyst Ag/FeWO4/g-C3N4. The characterization of the fabricated composite was done by Fourier transform infrared, scanning electron microscopy energy-dispersive X-ray, and X-ray diffraction. The Ag/FWO/GCN was used to degrade the rhodamine B (RhB) dye. Under sunlight, Ag/FeWO4/g-C3N4 showed enhanced photocatalytic degradation of rhodamine B dye, which was ascribed to the change in bandgap and reduced charge recombination. The parameters used for the optimization of the photocatalyst were pH, catalyst dose, oxidant dose, and irradiation time. The composite (Ag/FeWO4/g-C3N4) showed ~ 98% degradation of RhB dye under optimized conditions (i.e., pH = 8, catalyst dose = 50 mg/100 ml, oxidant dose = 9 mM, irradiation time = 120 min and RhB conc. 50 ppm).