One-step microwave synthesis of pure and Mn doped WO₃ nanoparticles and its structural, optical and electrochemical properties

In this report, we have successfully synthesized pristine and manganese (Mn) doped tungsten oxide (WO₃) nanoparticles by simple one step microwave irradiation method for the first time. The concentrations of Mn is varied from 0 to 10 wt%. Powder X-ray diffraction analysis suggest that both pure and Mn doped WO₃ samples crystalline with monoclinic phase have formed directly during the microwave irradiation process. Transmission electron micrographs reveal the spherical shaped morphology with average particle size around 20–35 nm. The optical band gap energy of WO₃ can be varied from 3.05 to 2.85 eV obtained by UV-DRS analyses with increasing the doping content of Mn. Most importantly, we demonstrate for the first times that Mn doped WO₃ nanoparticles are an excellent candidate for super capacitor applications. The electrochemical properties of pure and Mn doped WO₃ samples were evaluated by using cyclic voltammetry analyses. The results demonstrated that Mn doped WO₃ electrode exhibits excellent electrochemical performances (specific capacitance 620 F/g and charge transfer ability) for supercapacitors. The samples were further characterized by photoluminescence and Energy dispersive spectra analysis.