【作者】 李君敬；

【导师】 刘惠玲；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2013， 博士

【摘要】 氯代有机物由于具有毒性强、分布广、易在食物链中积累与传播，并且能对人的分泌系统造成严重的影响，因此它的环境影响及有效去除受到了研究者较多的关注。在众多的研究方法中，电催化因其效率高、无污染等优点而倍受青睐。钯修饰电极因在催化、加氢等领域有着巨大的优势而显现出良好的应用前景。在国内外研究的基础上，本论文制备了钯/泡沫镍、钯/聚苯胺/泡沫镍及钯/聚吡咯/泡沫镍三种复合电极，并采用扫描电子显微镜、透射电子显微镜、X-射线衍射、X-射线光电子能谱及傅立叶红外光谱对其结构及物理化学性能进行了表征分析，研究了复合电极对氯酚类化合物的脱氯性能，分析了改性复合电极增强的脱氯机制。采用恒电流电沉积法制备了钯/泡沫镍电极，并利用多种表征手段考察了所制备的钯/泡沫镍电极表观形貌、晶体结构及表面形态，并重点研究了钯/泡沫镍电极对一氯酚的电催化还原脱氯活性、动力学特性及稳定性。结果表明：钯/泡沫镍电极上钯颗粒呈树枝状，且为零价，并表现出良好的化学稳定性及脱氯活性，系列一氯酚的电催化还原脱氯反应为拟一级反应动力学。先将聚苯胺恒电流聚合在泡沫镍上，再将钯颗粒恒电流沉积在聚苯胺层上，制备了钯/聚苯胺/泡沫镍复合电极，并利用扫描电子显微镜、透射电子显微镜、X-射线衍射、傅立叶红外光谱及X-射线光电子能谱研究了其表观形貌、晶体结构及表面形态等物理化学性能，重点研究了不同聚合条件对复合电极形貌及结构与二氯酚的电化学脱氯行为的影响。结果表明钯/聚苯胺/泡沫镍复合电极中聚苯胺以针形存在，而Pd颗粒则以簇状结构分布在聚苯胺网络结构中，并主要以零价钯形式存在。聚苯胺的引入大大改善了钯颗粒的分散性。其中，最优的聚苯胺制备条件为：聚合电流为24mA，聚合温度为0℃，聚合时间为20min。先将聚吡咯恒电位聚合在泡沫镍上，再将钯颗粒恒电流沉积在聚吡咯层上，制备了钯/聚吡咯/泡沫镍复合电极，并用相关的表征手段研究了复合电极的表观形貌、晶体结构及表面形态等，重点考察了不同电聚合条件对其形貌及结构与二氯酚的电化学脱氯行为的影响。结果表明不同掺杂离子、应用电位、聚合温度及聚合时间等均对聚吡咯微球的表观形貌及分布有显著影响。结果表明：当掺杂离子为对甲苯磺酸，聚合电位为0.6V，聚合温度为0℃及聚合时间为20min时聚吡咯微球颗粒粒径最小、分布最均匀，为Pd颗粒的成核和生长提供了良好的环境。电催化还原2,4-二氯苯酚（2,4-DCP）的效率最高。考察了电极的稳定性，同时研究了了其对六种二氯苯酚同分异构体的脱氯路径、动力学及机理。结果发现：钯/聚吡咯/泡沫镍复合电极具有良好的稳定性及电化学还原脱氯活性，且对六种二氯苯酚同分异构体的电催化加氢脱氯结果表明：2,4-DCP的在反应时间为120min时的去除率最高，为91.1%，而3,5-DCP的去除率最低，为68%。此外，考察了六种二氯酚的电化学加氢脱氯各级反应动力学。更多还原

【Abstract】 Environmental effect and effective removal of chlorinated organic compounds have attracted many attentions due to its strong toxicity, widespread, and easy accumulation and migration in the food chain, as well as serious effect on human secretion system. Among the many methods, electrocatalysis was received many emphasis due to the high efficiency and non-pollution. In addition, Pd decorated electrode exhibited huge advantages and promising application in the research field of catalysis and hydrogenation. On the basis of the research at home and abroad, three kinds of composite electrodes such as Pd/Ni, Pd/PANI/Ni and Pd/PPY/Ni were prepared. The structures and physicochemical properties were investigated by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). In addition, dechlorination activities together with the dechlorination mechanism of the modified composite electrodes were proposed.Pd/Ni electrodes were prepared through galvanostatic method. Subsequently, the apparent morphologies, crystal structures and surface state of Pd/Ni electrodes prepared from different conditions were investigated by many techniques. Meanwhile, electrocatalytic dechlorination activity for monochlorphenol, dynamic characteristic and stability of the as-prepared Pd/Ni electrodes were mainly investigated. It was found that Pd particles existed in the form of dendritic structure and zero state, which exhibited excellent chemical-stability and dechlorination activity. Furthermore, the reactions fitted well with the first order kinetics function.Pd/PAIN/Ni composite electrodes were synthesized by electrochemical deposition method. Pysicochemical properties such as apparent morphologies, crystal structures and surface states were characterized through scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The effect of polymerization conditions on morphologies, structures and dechlorination activity for dichlorophen of Pd/PAIN/Ni composite electrodes were mainly studied. All results indicated that PPYs in the Pd/PANI/Ni composite electrode existed in the form of needle-shaped, while nulvalent Pd particles dispersed well as clusters in the network on PPYs, in which the optimal polymerization conditions were obtained with the polymerization current of24mA, temperature of0℃and time of20min, respectively.Pd/PPY/Ni composite electrodes were constructed through constant current cathodic electrodeposition. The apparent morphologies, crystal structures and surface states were studied by related techniques. Furthermore, the effect of polymerization conditions on morphologies, structures and dechlorination activity for dichlorophen was mainly investigated. Results showed that the dopant ions, applied potential, polymerization temperature and time exhibited significant influences on the apparent morphology and distribution of PPYs microspheres. Furthermore, as the polymerization process was continued20min under0.6V at0℃in the presence of toluenesulfonic acid, the minimum particle sizes and uniform distributions of PPYs microspheres were obtained, which provided a favorable condition for the crystallize and growth of Pd particle.The stability of Pd/PPY/Ni composite electrodes was investigated. In addition, the dechlorination activity for dichlorophen and its isomerides and dynamic characteristics were studied. It was found that Pd/PPY/Ni composite electrodes displayed excellent electrochemical reductive dechlorination activity. Besides, under120min, the dechlorination activity for2,4-dichlorophenol was91.1%, while3,5-chlorophenol was68%.更多还原