Abstract
Brick-shaped zinc tungstate nanoparticles have been synthesized by ecofriendly solvent-free process using molten salts. Zinc tungstate nanobricks (ZnWO
4
Nbs) were characterized by powder x-ray diffraction (PXRD), FTIR, Raman, energy dispersive and electron microscopic studies. ZnWO
4
Nbs are used as the multifunctional electrode materials to oxygen generation reactions (OGR), oxygen reduction reactions (ORR) and supercapacitors (SCs) as well as photo-catalysts in the waste-water treatment by the degradation of organic dyes. Low overpotential (
ƞ
10
= 0.475 V), low tafel slope (140 mV/dec), high current density (~70 mA/cm
2
) and good stability of the electrodes are the key results of the present studies for water electrolysis (OGR/ORR). ZnWO
4
Nbs have also shown great interest in supercapacitors with efficient charge–discharge activities in 1 M KOH. The specific capacitance and energy density of ZnWO
4
Nbs were found to be 250 F/g and 80 Wh/kg, respectively, at 5 mV/s, these values are relatively higher than that of previously reported specific capacitance and energy density value of metal tungstate nanoparticles. ZnWO
4
Nbs as the photo-catalysts work very significantly for photocatalytic degradation of aqueous MB dye solution (~85 % in 3 h) in neutral medium.
ZnWO
4
Nanobricks show significant multifunctional electro-chemical activities in alkaline medium and photocatalytic degradation of organic dye in neutral medium.
Highlights
Ecofriendly solvent-free Synthesis of ZnWO
4
Nanobricks (Nbs).
ZnWO
4
Nbs show admirable multifunctional electrochemical activities (OGR/ORR/SCs).
Low overpotential, low Tafel values, relatively high current density and good stability of electrode materials are significant for OGR and ORR.
ZnWO
4
Nbs exhibit efficient supercapacitor performances with the specific capacitance (250 F/g) and energy density (80 Wh/kg) at 5 mV/s in 1 M KOH.
ZnWO
4
Nbs also work as photo-catalysts to enhance the degradation of aqueous organic dyes.