One step green preparation of graphene/ZnO nanocomposite for electrochemical sensing

A disposable electrochemical sensor for determination of hydrogen peroxide (H₂O₂) was developed based on graphene/zinc oxide (ZnO) nanocomposite-modified screen printed carbon electrode (SPCE). The method adopted is facile, cost effective and avoids the conventional usage of harsh oxidants and acids. Graphite was exfoliated into graphene sheets via liquid phase exfoliation with the aid of ultrasonication, without going through the intermediate graphene oxide phases that can disrupt the pristine structure of the yield. The as-prepared graphene/ZnO nanocomposite was comprehensively characterized to investigate its morphology, crystallinity, composition, thickness and purity. The results clearly indicate that graphite was successfully exfoliated into graphene sheets and ZnO nanoparticles were well dispersed on the surface of graphene sheets. The electrochemical performance of the graphene/ZnO nanocomposite-modified SPCE was evaluated via cyclic voltammetry (CV) and amperometric technique. The resulting electrode displays excellent electrocatalytic activity towards the reduction of H₂O₂ in a linear range of 1 to 15 mM with a correlation coefficient of 0.9859. The facile and green approach used for the preparation of graphene/ZnO nanocomposite may open up new horizons in the production of cost-effective biosensors.