Jiang Guangming, Shi Xuelin, Cui Meiyang, Wang Weilu, Wang Peng, Johnson Grayson, Nie Yudong, Lv Xiaoshu, Zhang Xianming, Dong Fan, Zhang Sen
Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University, Chongqing 400067,China.
Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States.
ACS Appl Mater Interfaces. 2021 Jan 27;13(3):4072-4083. doi: 10.1021/acsami.0c20994. Epub 2021 Jan 13.
We present an enhanced catalytic efficiency of palladium (Pd) nanoparticles (NPs) for the electrocatalytic hydrodechlorination (EHDC) reaction by incorporating the tetraethylammonium chloride (TEAC) ligand into the surface of NPs. Both experimental and theoretical analyses reveal that the surface-adsorbed TEAC is converted to molecular amine (primarily triethylamine) under reductive potentials, forming a strong ligand-Pd interaction that is beneficial to the EHDC kinetics. Using the EHDC of 2,4-dichlorophenol (2,4-DCP), a dominant persistent pollutant identified by the U.S. Environmental Protection Agency, as an example, the Pd/amine composite delivers a mass activity of 2.32 min g and a specific activity of 0.16 min cm at -0.75 V versus Ag/AgCl, outperforming Pd and most of the previously reported catalysts. The mechanistic study reveals that the amine ligand offers three functions: the H-pumping effect, the electronic effect, and the steric effect, providing a favorable environment for the generation of reactive hydrogen radicals (H*) for hydrogenolysis of the C-Cl bond. It also weakens the adsorption strength of EHDC products, alleviating their poisoning on Pd. Investigation into the intermediate products of EHDC on Pd/amine and the biological safety of the 2,4-DCP-contaminated water after EHDC treatment demonstrates that EHDC on Pd/amine is environmentally benign for halogenated organic pollutant abatement. This work suggests that the tuning of NP catalysis using facile ligand post-treatment may lead to new strategies to improve EHDC for environmental remediation applications.
我们通过将四乙基氯化铵（TEAC）配体引入钯（Pd）纳米颗粒（NPs）表面，提高了其对电催化加氢脱氯（EHDC）反应的催化效率。实验和理论分析均表明，表面吸附的TEAC在还原电位下转化为分子胺（主要是三乙胺），形成了有利于EHDC动力学的强配体 - Pd相互作用。以美国环境保护局确定的主要持久性污染物2,4 - 二氯苯酚（2,4 - DCP）的EHDC为例，在相对于Ag/AgCl为 - 0.75 V的电位下，Pd/胺复合材料的质量活性为2.32 min g，比活性为0.16 min cm，优于Pd和大多数先前报道的催化剂。机理研究表明，胺配体具有三种功能：H泵浦效应、电子效应和空间效应，为生成用于C - Cl键氢解的活性氢自由基（H*）提供了有利环境。它还减弱了EHDC产物的吸附强度，减轻了它们对Pd的中毒作用。对Pd/胺上EHDC的中间产物以及EHDC处理后2,4 - DCP污染水的生物安全性进行研究表明，Pd/胺上的EHDC对于卤代有机污染物的去除在环境方面是良性的。这项工作表明，使用简便的配体后处理来调节NP催化可能会带来改善EHDC用于环境修复应用的新策略。
