A promising photoelectrochemical sensor based on a ZnO particle decorated N-doped reduced graphene oxide modified electrode for simultaneous determination of catechol and hydroquinone

Abstract

This paper describes the two-step synthesis of a nitrogen-doped reduced graphene oxide–ZnO (N-doped RGO–ZnO) nanocomposite and its photo electrochemical application. The novel photo electrochemical sensor fabricated from this ZnO–N-doped RGO nanocomposite exhibits superior performance over a glassy carbon or nitrogen-doped reduced GO nanocomposite for the simultaneous determination of hydroquinone (HQ) and catechol (CC). Cyclic voltammetry (CV) studies reveals that the N-doped RGO–ZnO electrode under optimal conditions shows a peak potential separation between HQ and CC of up to 112 mV in the presence of light, which is larger than an N-doped RGO electrode under the same conditions. Square wave voltammetry (SWV) studies of a system with co-existing HQ and CC show that the N-doped RGO–ZnO modified electrode exhibits a wide linear response range of 2–900 μM and 2–600 μM, respectively, with detection limits (S/N = 3) of 10 nM and 10 nM, respectively. The electrode also has good sensitivity, selectivity, high stability and reproducibility. This electrode sensor was further applied to determine HQ and CC in real samples with satisfactory results. The results demonstrate that the N-doped RGO–ZnO is a more robust and advanced carbon electrode material providing a promising platform for photo electrochemical sensors and photo electrocatalytic applications.