Facile hydrothermal synthesis of nickel tungstate (NiWO4) nanostructures with pronounced supercapacitor and electrochemical sensing activities

Abstract

Herein, we designed chain-like, round-shaped nickel tungstate (NiWO4) nanostructures by a simple hydrothermal method. The size of NiWO4 nanoparticles was between 20 and 100 nm and the average surface area was 101.4827 m2/g. Synthesized nanomaterial was investigated for electrochemical supercapacitor studies and charge–discharge capacity studies which demonstrated the enhanced specific capacitance. Results elaborate that NiWO4 synthesized at 180 °C and calcinated at 700 °C show enhanced specific capacitance 1524 F/g at a current density of 0.5 A/g. A maximum energy density of 32.27 WhKg−1 was achieved at a power density of 2206 Wkg−1. Furthermore, the successfully assembled supercapacitor also showed the largest charge/discharge time as 1353 s, corresponding to a current density of 0.5 A/g. Besides, NiWO4 nanostructures depicted promising electrochemical sensing capabilities when deposited on glassy carbon electrodes for the detection of ascorbic acid. The NiWO4 modified electrode showed excellent sensitivity for ascorbic acid with a limit of detection of 2.37 mM and 0.38 mM for cvp1 and cvp2, respectively. Furthermore, the electrochemical behavior of NiWO4 modified GCE for ascorbic acid was inquired in different electrolytes and the highest intensity was observed in LiSO4 electrolyte. Based on these findings, the present work might generate new intuition for the synthesis of different combinations of transition metal oxide nanostructures and their applications as supercapacitors and electrochemical sensors.