Hydrothermally produced Mo-doped WO3 nanoparticles and their enhanced photocatalytic and electrochemical properties

Abstract

Abstract In this study, pure WO3 as well as doped with molybdenum (0, 2.5, and 5 at. wt. %) nanoparticles were successfully synthesized via sol-gel processing followed by a hydrothermal approach. The physicochemical characteristics of WO3 and Mo-doped WO3 nanoparticles were thoroughly characterized using techniques, including XPS, FESEM, HRTEM, UV-visible, photoluminescence, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results predicted that the insertion of Mo into the WO3 lattice had a prominent effect on morphology as well as microstructure. The addition of Mo ions in WO3 NPs narrowed the bandgap of WO3 and enhanced its ability of light absorption. The photocatalytic behavior of prepared nanoparticles was investigated through the photodegradation of an organic dye (methyl orange, MO) in an aqueous solution in presence of UV-Visible light. Photocatalytic activity of WO3 nanoparticles could considerably be increased with Mo doping, which might be due to the redshift of absorption edge as well as the lowering of recombination rate of electron-hole pairs caused by the trapping of charge carriers through crystal defects. The electrochemical properties of undoped WO3 nanoparticles, and Ag NPs loaded WO3 nanocomposite, were investigated through cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance measurements and analysis. The present findings recommend that 5% Mo-doped WO3 nanocomposite provides a promising direction for the development of high quality, effective and reliable photocatalytic and electrode material for organic dyes degradation and hybrid supercapacitors respectively.