Effect of zinc precursors on the hydrogen evolution reaction and electrochemical corrosion studies of ZnWO4 nanoparticles synthesized by hot injection method

Abstract

ZnWO4 nanoparticles were synthesized by a hot injection method using different zinc precursors (zinc nitrate, zinc acetate, zinc sulphate and zinc chloride) with sodium tungstate. Similarly, the ZnWO4 particles were prepared by co-precipitation and solid-state method for comparative analysis. The phase formation temperature of ZnWO4 was identified through thermal analysis. X-Ray diffraction (XRD) analysis enumerates that the formation of a single-phase monoclinic wolframite structure with the space group P2/c. The characteristic functional groups of Zn-O, Zn-O-W, and W-O were identified through Fourier Transform Infrared Spectroscopy (FTIR). The microscopic images revealed that the formation of spherical shape particles in size range between 60 and 100 nm. The room temperature electrical conductivity was measured using LCR meter, and it shows that the conductivity is in the range of 2.2 × 10−5 to 6.2 × 10−6 S.cm−1. The calculated corrosion rate of ZnWO4 using Tafel Polarization curve in 1 M H2SO4 at 1 mV s−1 was 0.2554 mmpy. The electrocatalytic activity towards the hydrogen evolution reaction (HER) was studied using linear sweep voltammogram in 1 M H2SO4 solution at a scan rate of 1 mV s−1. Further, the zinc acetate precursor assisted particles have shown a low onset potential (0.42 V) and higher current density (−228.52 mA cm−2) in the potential range of 0 to −1.0 V compared with other samples.