掺氮金刚石电极性能及其氧化降解硝基苯研究

Nitrogen-doped Diamond Electrode Property and Anodic Catalytic Degradation of Nitrobenzene

采用热阴极直流辉光等离子体化学气相沉积法制备亚微米晶氮掺杂金刚石膜(NDD),采用SEM分析样品的表面形貌,分别用Hall测试和循环伏安法测试氮掺杂金刚石电极的电学和电化学性能。实验结果表明,当氮气流量低于30 sccm时,膜的电导率随氮气流量的增大略有提高;氮气流量继续增大则电导率迅速下降,电导率最大为5.091 S/cm。氮掺杂金刚石电极具有较好的伏安性能,在酸性、中性和碱性介质中均具有较宽的电位窗口和较低的背景电流。以硝基苯为目标污染物测试NDD材料作为阳极氧化降解的电催化性能。在0.1 mol/L Na2SO4溶液的支持电解质中,以氮掺杂金刚石为阳极降解0.5 mmol/L的硝基苯,反应时间300 min,硝基苯的降解率达到94%,化学需氧量(COD)去除率约68%。

A series of nitrogen-doped diamond（NDD） film electrodes were synthesis by hot cathode direct current plasma chemical vapor deposition（HCDCPCVD） method with varied ratio CH4/H2/N2 gas mixture.Morphologies of diamond films were characterized by SEM.Electrical and electrochemical properties of nitrogen-doped diamond electrodes were characterized by Hall test and cyclic voltammetry.The results show that when the nitrogen flow rate is less than 30 sccm,the conductivity of the film increases slightly with the increase of the nitrogen flow rate.As the nitrogen flow rate continues to increase,the conductivity decreases rapidly,showing the maximum electroconductibility of 5.091 S/cm.The nitrogen-doped diamond electrode has good voltammetric performance with a wide potential window and a low background current in acidic,neutral and alkaline media.Properties of anodic oxidation degradation of nitrogen-doped diamond electrodes were tested using nitrobenzene as target pollutant.In the supporting electrolyte of 0.1 mol/L Na2SO4 solution,0.5 mmol/L nitrobenzene is decomposed using the nitrogendoped diamond as anode.After reaction for 300 min,degradation rate of the nitrobenzene reaches 94%,and COD（Chemical Oxygen Demand） removal rate is about 68%.