Insight into the investigation on nanostructured defect pyrochlore Bi2-xFexWO6 and its photocatalytic degradation of mixed cationic dyes

Abstract

Structural and band gap modifications by substituting Fe ions into the structure of Bi2WO6 for enhanced optical property and photocatalytic activity has been studied in this work. Nanostructured Bi2-xFexWO6 were synthesized by facile co-precipitation technique. X-ray Diffraction Studies (XRD) and WH plot derived from the diffraction pattern conveyed the structural and micro-strain induced due to the substitution of Fe ions. FT-IR and Raman studies proved to be in correspondence with XRD analysis. The reduced particle size and the transformation from cubic to nano regime spherical morphology were observed using SEM and HR-TEM imaging techniques. UV-DRS analysis displayed reduced band gap from 2.7 eV to 1.72 eV and the shift in band edge positions enhancing optimal use of visible light. Furthermore, the chemical states analyzed using XPS measurements confirmed the presence of Fe3+, Bi3+ and formation of oxygen vacancies. The Photoluminescence (PL) and Electrochemical Impedance (EIS) confirmed efficient charge separation and migration of photo induced charge carriers. The visible degradation of RhB, AO and the mixed dyes (RhB + AO) confirmed the efficient photocatalytic efficiency for optimal amount of Fe ions concentration.