亚硝酸盐在氮掺杂石墨烯-CuS复合材料修饰电极上的电化学响应及测定

Electrochemical Response and Determination of Nitrite on a CuS-Nitrogen Doped Graphene Modified Electrode

采用简单的水热反应制备氮掺杂石墨烯(NG)-CuS复合材料,并采用X-射线衍射(XRD)、扫描电镜(SEM)和X-射线光电子能谱(XPS)对该材料进行了表征。将该材料修饰至玻碳电极(GCE)上研究了其对亚硝酸盐的电化学响应。结果表明,NG-CuS/GCE具有大的比表面积和高导电性,从而对亚硝酸盐表现出好的电催化效果。在最佳实验条件下,NG-CuS/GCE对亚硝酸盐的响应在3s之内达到稳定,其催化氧化峰电流和亚硝酸盐浓度在0.1μmol/L^14.02 mmol/L之间呈良好的线性关系,检测限(S/N=3)低至33nmol/L。该修饰电极测定亚硝酸盐的稳定性、重现性和选择性好,已经成功用于实际样品中亚硝酸盐的测定。

In this work, N-doped graphene （NG）-CuS binary composite was synthesized by a facile hydrothermal method and characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. Then the electrochemical oxidation behavior of nitrite at NG-CuS composites modified glassy carbon electrode （NG-CuS/GCE） was investigated in pH = 6. 0 phosphate buffer solution by cyclic voltarnmetry. The experimental results indicated that, comparing with GCE, NG/GCE and CuS/GCE, NG-CuS/GCE exhibited an excellent electrocatalytic activity towards nitrite with a low overvoltage and pronounced current response owing to excellent conductivity and high surface area of NG substrate and fast electron transfer of CuS. Under the optimized conditions,the proposed electrochemical nitrite sensor showed a rapid response to nitrite within 3 s and a wide linear calibration plot ranging from 0.1 μmol/L to 14.02 mmool/L, with a detection limit of 33 nmol/L. Moreover, the modified electrode showed good stability,reproducibility and selectivity. The proposed method was further used to determine nitrite in real samples with satisfactory results.