Enhanced activity for non-enzymatic glucose biosensor by facile electro-deposition of cauliflower-like NiWO4 nanostructures

This work introduces simple electrodeposition of nickel tungstate nanostructures (NiWO4 NSs) as an electrocatalyst material for the development of a non-enzymatic glucose biosensor. We report a straightforward route for electrosynthesis of NiWO4 NSs on the glassy carbon electrode (GCE) surface by performing two electrochemical steps for the first time. In the first step, the Ni–W alloy was electrodeposited on carbon substrate at a constant potential of -1.4 V (vs. SCE) for 60 s in an ammoniacal buffer (pH = 8.0) containing an appropriate amount of NiSO4 and Na2WO4. 2H2O. In the next step, Ni–W alloy was converted to the cauliflower nanostructured NiWO4 by applying a cyclic voltammetric (CV) treatment in 1.0 M NaOH solution for 15 cycles at the scan rate 50 mV s−1. The surface morphology, elemental composition, crystal structure of NiWO4 NSs were studied by FESEM, EDX, and XRD analysis, respectively. The NiWO4 NSs/GCE nanosensor exhibited excellent electrocatalytic activity towards glucose in an alkaline medium. The proposed non-enzymatic glucose biosensor possessed excellent selectivity obtained at potential (0.6 V vs. SCE) in KOH 0.1 M, and outstanding long term stability. Furthermore, it showed a low detection limit of 0.15 µM with a high sensitivity of 1200 μA mM−1 cm−2 over the linear range of 0.5–280 µM in KOH 0.1 M. Finally, the practical application of the proposed sensor was successfully evaluated by determining the glucose concentration of human blood with the satisfactory results.