We report on the synthesis of zirconium dioxide-reduced graphene oxide composite (ZrO2-rGO) and its application as a novel architecture for electrochemical sensing and biosensing purposes. ZrO2-rGO hybrid is synthesized through a simple one-step hydrothermal route, where the reduction of GO and the in-situ generation of ZrO2 nanoparticles (NPs) occurred simultaneously. Characterization of the resultant hybrid material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy clearly indicated the homogeneous dispersion of ZrO2 NPs with particle sizes of ∼5 nm on rGO sheets. The potential application of ZrO2-rGO modified glassy carbon electrode (ZrO2-rGO/GC) for electroanalytical purposes was demonstrated by using several important electroactive compounds as representative examples (i.e., O2, hydrogen peroxide (H2O2), glucose, ascorbic acid (AA), dopamine (DA) and uric acid (UA)). Electrochemical control experiments by using different composites of ZrO2/graphite, ZrO2/Active Carbon and ZrO2 electrodeposited on activated GC electrode revealed that the ZrO2-rGO composite possessed superior electrocatalytic activitiy towards the catalytic reduction of O2 and H2O2 at more reduced overpotentials. The linear range of H2O2 concentration was from 0.10 to 1340 μM with the detection limit of 20 nM (S/N = 3). Furthermore, via immobilization of glucose oxidase (GOx) enzyme onto the ZrO2-rGO/GC electrode surface, the ability of modified electrode for biosensing glucose was demonstrated. In addition, the modified electrode can be applied for simultaneous detection of AA, DA and UA, using differential pulse voltammetry as measuring technique. We envisage that the ZrO2-rGO hybrid may hold great promise for the development of electrochemical sensors and biosensors as well as other applications, such as supercapacitors and fuel cells.
