中文摘要：

采用氢气还原法制备出Pd／C催化剂，利用循环伏安曲线（CV）对氧在Pd／C催化剂上的电化学还原行为进行了分析，并由催化剂制备成Pd／C气体扩散阴极，采用先通H2后通空气的方式在隔膜电解体系中对五氯酚钠进行降解，比较了不同电极体系下五氯酚钠的去除效果．结果表明，在阴极室，Pd／C气体扩散电极通过外界曝气提供的O2在阴极还原产生H2O2，电解100min后H2O2的稳定浓度达到9．8mg／L．实验制备的Pd／C气体扩散阴极既对五氯酚钠具有还原脱氯作用（通人H2时），又促进O2还原生成H2O2（通入O2时），它对五氯酚钠的去除效果要好于不掺杂Pd的气体扩散阴极．反应120min后，五氯酚钠平均转化率和脱氯率均超过80％，反应200min后TOC平均去除率分别超过75％．采用高效液相色谱（HPLC）等手段分析出五氯酚钠在阴极室还原脱氯的中间产物主要是苯酚，Pd／C气体扩散阴极利用电化学还原脱氯和阴阳极同时氧化相结合对氯酚类有机物的降解是可行的．

英文摘要：

Pd/C catalyst was prepared by hydrogen reduction method and used for the Pd/C gas-diffusion electrode. It was characterized by cyclic voltammetry （CV） techniques.The electrochemical degradation of sodium pentachlorophenol （PCP-Na） was investigated in a diaphragm electrolysis device, feeding firstly with hydrogen gas then with air, using the Pd/C gas-diffusion electrode and the carbon/polytetrafluoroethylene （C/PTFE） gas-diffusion electrode as the cathode, respectively. The results indicate that the two-electron reduction from O2 to hydrogen peroxide （H2O2 ） is produced at the Pd/C gas-diffusion electrode, and the accumulated H2O2 in the cathodic compartment reach to the steady concentration of 9.8 mg/L after 100 min. The Pd/C gas-diffusion cathode can reductively dechlorinate PCP-Na by feeding hydrogen gas, and accelerate the two-electron reduction of O2 to hydrogen peroxide （H2O2） by feeding air. Therefore, both the removal efficiency and the dechlorination degree of PCP-Na exceed 80% after 100 min, and the average removal efficiency of PCP-Na in terms of total organic carbon （TOC） exceeds 75% after 200 min by using Pd/C gas-diffusion cathode, which is better than that of the C/PTFE gas-diffusion cathode. High performance liquid chromatography （HPLC） allows identifying phenol as the dechlorination product.