非晶态Pd-P/聚吡咯/泡沫Ni电极对五氯苯酚的催化还原

电催化还原氯代有机物具有效率高和环境友好等优点。研究采用电化学沉积法在泡沫Ni上制备了非晶态Pd-P/聚吡咯/泡沫Ni(Pd-P/PPy/foam Ni)复合电极,用于电催化还原法去除水中的五氯苯酚(PCP)。扫描电镜(SEM)、透射电镜(TEM)、X射线衍射分析(XRD)和X射线光电子能谱分析(XPS)等表征结果表明,掺杂P使Pd催化剂分散均匀,粒径变小,且由晶态结构转变为非晶态。由电催化还原PCP发现,掺杂P明显提高了电极的催化活性。在n(Pd)/n(P)为1:3,Pd负载量为0.15 mg/cm^2,H2SO4浓度为0.2 mol/L,阴极电位为–1.2 V条件下,处理180 min后,PCP的降解率达到90.8%。另外,Pd-P/PPy/foam Ni电极重复使用8次,仍保持良好的稳定性。

Electrochemical dechlorination of chloroform in neutral aqueous solution on palladium/foam-nickel and palladium/polymeric pyrrole film/foam-nickel electrodes

Electrochemical dechlorination of chloroform in neutral aqueous solution was investigated using palladium-loaded electrodes at ambient temperature. Palladium/foam-nickel （Pd/foam-Ni） and palladium/polymeric pyrrole film/foam-nickel （Pd/PPy/foam-Ni） composite electrodes which provided catalytic surface for reductive dechlorination of chloroform in aqueous solution were prepared using an electrodepositing method. Scanning electron microscope （SEM） micrographs showed that polymeric pyrrole film modified the electrode-surface characteristics and resulted in the uniform dispersion of needle-shaped palladium particles on foam-Ni supporting electrode. The experimental results of dechlorination indicated that the removal efficiency of chloroform and current efficiency in neutral aqueous solution on Pd/PPy/foam-Ni electrode could be up to 36.8% and 33.0% at dechlorination current of 0.1 mA and dechlorination time of 180 min, which is much higher than that of Pd/foam-Ni electrode.

酸性体系中Pd／PPy／foam-Ni电极电化学还原三氯甲烷

在沉积电流密度5mA.cm-2,沉积时间40min条件下,通过电沉积方法制备Pd/PPy/泡沫镍(foam-Ni)电极,以Pd/PPy/foam-Ni电极为阴极研究酸性体系中三氯甲烷的电化学还原脱氯,实验在室温条件下进行.采用循环伏安法对电极进行测试,Pd/PPy/foam-Ni电极在-500mV(vsHg/Hg2SO4)左右获得很大的氢吸附峰电流值,峰电流值为-100mA.扫描电镜(SEM)分析表明,聚吡咯的引入改变了Pd在电极表面的沉积形态,使电极表面具有很好的空间延伸性.在酸性体系中进行Pd/PPy/foam-Ni电极对三氯甲烷的电化学还原脱氯实验,结果表明,综合考虑三氯甲烷去除率及脱氯过程电流效率,在保证脱氯过程电流效率为44.17%的条件下,三氯甲烷的去除率为49.23%,此时最佳脱氯电流密度为0.05mA.cm-2,最佳脱氯时间为180min,实现了在酸性水溶液体系中,低初始浓度三氯甲烷较好的脱氯效果.