中文摘要：

以三聚氰胺为原料,利用热缩聚法制备了类石墨氮化碳（g-C_3N_4）,并采用X射线衍射（XRD）、扫描电镜（SEM）、红外光谱等方法对其进行表征。然后将g-C_3N_4超声分散于Nafion溶液中,将所得悬浊液修饰到玻碳电极上,制备用于检测硝基苯的电化学传感器（g-C_3N_4/Nafion/GCE）。采用循环伏安法、方波伏安法研究了硝基苯在该电极上的电化学行为。在优化实验条件下,硝基苯在该电极上的方波伏安还原峰电流与其浓度在4.0×10^-6~6.0×10-4mol/L范围内呈良好的线性关系,相关系数（r）为0.999 8,检出限为4.0×10^-7mol/L。按照国家标准方法对实际水样进行检测,未检测出硝基苯。配制两个浓度水平硝基苯的模拟水样进行加标回收实验,其回收率分别为102.1%和99.9%。用气相色谱法做对照实验,结果表明本方法与气相色谱法的测定结果无显著性差异。

英文摘要：

In this study, graphitic carbon nitride （ g - C3 N4 ） was synthesized by thermal condensa- tion with melamine, and characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and infrared spectroscopy. Graphitic carbon nitride was dispersed in Nation solution by ultra- sound to prepare suspension liquid which was modified onto the surface of a glassy carbon electrode （GCE） to prepare an electrochemical sensor（g- C3N,/Nation/GCE） for nitrobenzene. The volta- mmetric behaviours of nitrobenzene at the g - C3N4/Nafion/GCE were studied by cyclic voltammetry and square-wave voltammetry（SWV）. Under the optimal conditions, the cathodic peak current of ni- trobenzene showed a highly linear increase with nitrobenzene concentrations over the range of 4.0 ×10 -6 -6.0 × 10 -4 mol/L with a correlation coefficient（r） of 0. 999 8. The detection limit was 4. 0× 10-7 mol/L. The concentration values in real water samples were determined by the national standard method. No SWV response corresponding to nitrobenzene was observed when the real water samples were analysed. Simulated water samples therefore were prepared, and standard -additions method was adopted to estimate the recorvery. The recoveries at two spiked concentration levels were 102. 1% and 99.9% , respectively. No obvious differences were found between the proposed method and the gas chromatographic method.