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

In this study, pure WO₃ as well as doped with molybdenum (0, 2.5, and 5 at%) 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 and electrochemical impedance spectroscopy. 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. Band gap energy of pure WO₃ nanoparticles is reduced from 2.77 to 2.49 eV with Mo (5 at%) doping. The photocatalytic behaviour 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 degradation efficiency of photocatalyst against methyl orange (MO) dye is enhanced from 71.1 to 86.1% with the incorporation of Mo ions in WO₃.The electrochemical properties of undoped WO₃ nanoparticles, and Mo-doped WO₃ nanocomposite, were investigated through cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance measurements and analysis. The specific capacitance is increased from 255.6 to 488.9 Fg⁻¹ through Mo (5 at%) doping in WO₃ NPs. 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. [ABSTRACT FROM AUTHOR]