Synthesis of a ZnO nanorod/CVD graphene composite for simultaneous sensing of dihydroxybenzene isomers

A few-layered graphene nanosheets on a Ta thin film were synthesized by a direct current (DC) arc plasma jet chemical vapor deposition (CVD) process that does not critically depend on cooling rates. The thickness of the graphene layer is about 20 mu m, and the graphene sheets superimposed transversely on the outermost layer become a blooming bouquet. This structure is especially suitable as an electrode sensor. The ZnO nanorods have excellent electrochemical performance, and thus we combined ZnO nanorods and CVD graphene for a ZnO/graphene/Ta sensing electrode. The electrochemical oxidation of hydroquinone (HQ), catechol (CC), and resorcinol (RC) were investigated using cyclic voltammetry at the ZnO/graphene/Ta electrode. The results showed that it was feasible to simultaneously measure HQ, CC, and RC. The linear response ranges for HQ, CC, and RC were 0-70, 0-80, and 0-700 mu mol L-1. The detection limits (S/N = 3) were 0.1, 0.2, and 1 mu mol L-1, respectively. The ZnO/graphene layer shows high electrocatalytic activity toward the redox reaction of HQ, CC, and RC. This activity had high selectivity, high sensitivity and low detection limits. (C) 2015 Elsevier Ltd. All rights reserved.