Ni nanoparticle-decorated reduced graphene oxide for non-enzymatic glucose sensing: An experimental and modeling study

In this study, we used a facile approach to decorate Ni nanoparticles (Ni-NPs) with ethylene glycol followed by their adsorption on reduced graphene oxide (rGO) nanosheets for the development of enzyme free electrochemical glucose sensor. The effect of Ni-NP content (0.14, 0.28, 0.42, and 0.56 wt.%) on electrochemical properties and the molecular interaction of glucose with Ni-NPs/rGO in glucose sensing were evaluated. Ni-NPs/rGO showed significantly higher electrochemical performance for the glucose oxidation in alkaline solution compared to rGO. Specifically, 0.42% Ni-NPs/rGO revealed excellent performance for glucose determination with a wide linear range (0.25 μM to 1200 μM), a highly reproducible response and long-term stability with the calculated detection limit of 0.01 μM. Moreover, the reliability of the Ni-NPs/rGO sensor was confirmed by evaluating glucose concentration in human blood serum. Ab initio calculations were employed to reveal molecular interactions of glucose with Ni-NPs/rGO. The results showed Ni13 cluster with icosahedral geometry facing the graphene sheet is the most stable structure. Furthermore, the glucose molecule was able to adsorb on the graphene sheet through Ni13 nanoclusters and the adsorption process is closely dependent on the orientation of Ni13 nanoclusters.