Construction And Electrocatalysis Investigation Of Hydrogen Peroxide Based On Novel Nanocomposites Modified Electrodes

Due to the excellent comprehensive properties, nanocomposites have been widely applied in catalysis,pharmaceutical, health, environmental monitoring and other fields. A novel modified electrode constructedby the new nanocomposites is used for chemical detection, which is very meaningful for improving thesensitivity and selectivity of the analyte. Hydrogen peroxide is a very simple compound in nature, and palysa great important role in biological and social production processes. Based on these, differentnanocomposites were synthesized and used to modify the electrodes, which were applied to detect thehydrogen peroxide in actual samples. The main research work is described as follows:1. A novel Prussian blue/copper-gold bimetallic nano-particles hybrid film modified electrode was preparedby electrochemical deposition on a glassy carbon electrode (PB/Cu-AuNPs/GCE). Morphology andelectrochemistry of this electrode were studied by UV-vis spectroscopy, scanning electron microscopy, X-raydiffraction, cyclic voltammetry and electrochemical impedance spectroscopy. The sensor showedsignificantly better electrocatalytic activity for the reduction of hydrogen peroxide as comparison with thesingle PB/GCE and PB/AuNPs/GCE; this was attributed to the synergistic effect of PB and Cu-Au bimetallicnano-particles. Also, the sensor demonstrated an overall high level of performance for the analysis of H2O2with concentration range-2×10-6mol L-1~8.4×10-4mol L-1.2. We report on a modified glassy carbon electrode (GCE) for sensing hydrogen peroxide (H2O2). It wasconstructed by consecutive electrochemical deposition of poly(anthranilic acid) and poly(diphenylaminesulfonate) on the GCE, followed by deposition of copper oxide (CuO). The morphology and electrochemistryof the modified electrode was characterized by atomic force microscopy, X-ray diffraction, and by cyclicvoltammetry and electrochemical impedance spectroscopy. The catalytic performance of the sensor wasstudied by differential pulse voltammetry under optimized conditions. This biomimetic sensor displayedsignificantly better electrocatalytic activity for the reduction with H2O2in comparison to a GCE without orwith modification with CuO or polymer films alone. Response to H2O2is linear in the range between5×10-6mol L-1~11×10-3mol L-1, and the detection limit is1.8×10-7mol L-1(at an S/N of3).3. Hydrogen peroxide is an important analyte in biochemical, industrial and environmental systems.Therefore, development of novel rapid and sensitive analytical methods is useful. In this work, a hemin-graphene nano-sheets (H-GNs)/gold nano-particles (AuNPs) electrochemical biosensor for the detection ofhydrogen peroxide (H2O2) was researched and developed; it was constructed by consecutive, selectivemodification of the GCE electrode. Performance of the H-GNs/AuNPs/GCE was investigated by chronoamperometry, and AFM measurements suggested that the graphene flakes thickness was~1.3nm andthat of H-GNs was~1.8nm, which ultimarely indicated that each hemin layer was~0.25. This biosensorshowed significantly better electrocatalytic activity for the reduction of hydrogen peroxide in comparisonwith the simpler AuNPs/GCE and H-GNs/GCE, and it displayed a linear response to the reduction of H2O2range from3×10-7mol L-1to1.8×10-3mol L-1with a detection limit of1.1×10-7mol L-1(S/N=3), highsensitivity of2774.8A mM-1cm-2, and a rapid response, which reached95%of the steady state conditionwithin5s. In addition, the biosensor was unaffected by many interfering substances, and was stable overtime. Thus, this biosensor was demonstrated to be potentially suitable for H2O2analysis in many types ofsample.4. The self–assembly of layered molybdenum disulfide-graphene (MoS2-Gr) and horseradish peroxidase(HRP) by electrostatic attraction into novel hybrid nanomaterial (HRP-MoS2-Gr) is reported. The propertiesof the MoS2-Gr were characterized by X-ray diffraction (XRD), high–resolution transmission electronmicroscopy (TEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). UV-visand Fourier transform infrared spectroscopy (FT-IR) indicate that the native structure of the HRP ismaintained after the assembly, implying good biocompatibility of MoS2-Gr nanocomposite. Furthermore, theHRP-MoS2-Gr composite is utilized as a biosensor, which displays electrocatalytic activity to hydrogenperoxide (H2O2) with high sensitivity (679.7A mM–1cm–2), wide linear range (2×10-7mol L-1~1.103×10-3mol L-1), low detection limit (4.9×10-8mol L-1), and fast amperometric response. In addition, the biosensoralso exhibits strong anti–interference ability, excellent stability and good reproducibility. These desirableelectrochemical performances are attributed to the well biocompatibility and electron transport efficiency ofMoS2-Gr, as well as the high loading of HRP. Therefore, this biosensor is potentially suitable for H2O2analysis in environmental, pharmaceutical, food or industrial applications.