Defect rich Ni/NiO-graphene heterostructures with oxygen bridges for enhanced electrocatalytic glucose oxidation towards selective sensing

Defect rich Ni/NiO-graphene heterostructures were developed by combining electrocatalytically active Ni/NiO nanocomposite with graphene sheets using a facile single step solution combustion method. The synthesised electrocatalyst was characterized using XRD, Raman, FTIR, XPS, FESEM, TEM and HRTEM techniques. Ni-O-C linkage was evidenced from XPS spectrum in concurrent with G-band shift in Raman spectrum showed the effective integration of active nanocomposite with graphene sheets. Moreover, the wide distribution of active nanocomposite material on graphene sheets with a greater number of defect sites within NiO lattices would expose catalytically active sites for electrochemical redox reaction and synergistic effects of these heterostructures on the electrochemical behaviour of Ni/NiO-GS hybrid nanocomposite employing EIS, CV and CA techniques were discussed. Excellent improvement in the Ni2+/Ni3+ redox activity and enhancement in the glucose oxidative property of Ni/NiO-GS/GCE with respect to Ni/NiO/GCE was contributed to the availability of more electrochemical active surface area and the combined effect of increased mass transport and charge transfer kinetics. The amperometry response of Ni/NiO-GS/GCE towards glucose over a wide linear range (0.5 mM-7.5 mM) with good sensitivity (696 mu A mM-1 cm-2) and high correlation coefficient (0.9959) at an applied potential of about 0.495 V vs Ag/AgCl with anti-interference ability, repeatable and reproducible glucose oxidative current responds with an estimated relative standard deviation of 0.018 and 0.014 respectively makes it as a prospective electrode material for cost-effective glucose selective sensor.

Automated summary

Defect rich Ni/NiO-graphene heterostructures were developed through a facile method combining electrocatalytically active Ni/NiO nanocomposite with graphene sheets. The heterostructures exhibited enhanced redox activity and glucose oxidative properties. The material demonstrated a wide linear range, high sensitivity, and good anti-interference ability, making it a potential electrode material for cost-effective glucose selective sensors.