Reduced Graphene Oxide/Au Nanoparticle Codecorated Glassy Carbon Electrode And Their Electrochemical Application

Environmental pollutants, especially the environmental pollutants with high toxicity, areserious threat to human. It is necessary for human healthy and environmental security todevelop efficient methods for the determination of environmental pollutants. Au nanoparticles(AuNPs), which possess good electrical conductivity, have been proved to haveelectrocatalytic activity towards4-nitrophenol and trivalent arsenic ion. When combined withgraphene, they could not only keep the advantages of themselves, but also enhance theirelectrocatalysis towards4-nitrophenol and trivalent arsenic ion through combining theexcellent adsorption capacity and electrical conductivity that might generate synergic effectwith Au nanoparticle. Herein, the thesis systematically studied the detection effect of4-nitrophenol and trivalent arsenic ion using reduced graphene oxide (RGO)/Aunanoparticle codecorated glass carbon electrode (GCE). The main studies of this thesis aresummarized as follows:1. RGO/Au codecorated GCE fabricated by step-by-step electrodepositionThe RGO film was first deposited onto a glassy carbon electrode by cyclic voltammetryfrom-1.4V to0.6V, and then AuNPs were electrochemically deposited onto the RGO filmby using the constant potential process at-0.3V. The morphology and electrochemicalproperties of the RGO/AuNPs composite were investigated. The synergic effect of AuNPsand RGO nanosheets as co-modifiers greatly facilitates electron-transfer processes betweenthe electrolyte and the GCE, and thus leads to a remarkably improved sensitivity for4-NPdetection. Two detection modes, differential pulse voltammetry (DPV) and square wavevoltammetry (SWV), were applied. Wide linear range of0.05-2.0μM and4.0-100μM forDPV and0.05-2.0μM for SWV were obtained, respectively. The limit of detection (LOD) of4-NP was0.01μM and0.02μM for DPV and SWV, respectively. This sensor wassuccessfully used in the detection of real water samples from Xiangjiang River. This methodis simple and green without involving a toxic reductant.2. RGO/Au codecorated GCE fabricated by one-step eletrodepositionAu/reduced graphene oxide co-decorated glassy carbon electrode was successfully preparedthrough a facile one-step deposition process by cyclic voltammetry from-1.6V to0.6V.After the optimization of detection condition, the sensor showed good selectivity andsensitivity towards trivalent arsenic ion. By anodic stripping voltammetry, the linear range of0.0830μg/L for DPV was obtained. When choosing triple noise value as the minimumcurrent value, the LOD was calculated to be6ng/L. This sensing system showed stable andreliable performance in determining real water samples.