Carbon tetrachloride (CT), a common persistent pollutant in groundwater, has attracted widespread attention from environmental researchers. The dechlorination from CT to combustible hydrocarbons not only represents the removal of contaminants, but also offers the possibility of recovering carbon resources from water. In this work, we used the coprecipitation of Fe(II) and Pd(II) to synthesize Pd-Fe hydroxides for the dechlorination of CT. When Pd and Fe dosages were 0.4 and 5 mM respectively, CT with 26 µM concentration can be fast removed within 5 min, and 43.3 % of CH and 11.6 % of CH (mol%) were generated after 110 min. The alkaline condition was more conducive to the complete dechlorination of CT comparing with acidic and neutral conditions. During the olation process, Fe(II) as electron donor transferred electrons to Pd(II) to form Pd(0) clusters. Pd(0) active sites act on the binding of CT and transfer electron to H/HO to form adsorbed atomic hydrogen (H•). The adsorbed CT molecules on the surface of Pd-Fe hydroxides undergo continuous dechlorination to form CH and CH through the attack of H• and direct electron transfer. In real groundwater applications, CT was rapidly removed, with CH and CH yields reaching 24.5 % and 4.6 % (mol%), respectively. Encouragingly, incomplete dechlorinated products, including chloroform and dichloromethane, did not show signs of subsequent rebound even after 60 min. Furthermore, Pd-Fe hydroxides also exhibit resistance to the oxidation effects of dissolved oxygen, which demonstrates the promising application prospects.

中文翻译：

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Pd-Fe氢氧化物通过原子氢攻击和直接电子转移催化四氯化碳脱氯生成可燃烃

四氯化碳（CT）作为地下水中常见的持久性污染物，引起了环境研究者的广泛关注。从CT脱氯到可燃碳氢化合物不仅代表了污染物的去除，而且还提供了从水中回收碳资源的可能性。在这项工作中，我们利用 Fe(II) 和 Pd(II) 的共沉淀法合成了 Pd-Fe 氢氧化物，用于 CT 脱氯。当Pd和Fe剂量分别为0.4和5 mM时，浓度为26 µM的CT可在5 min内快速去除，110 min后产生43.3 %的CH和11.6 %的CH (mol%)。与酸性和中性条件相比，碱性条件更有利于CT脱氯完全。在光化过程中，Fe(II)作为电子供体将电子转移到Pd(II)上形成Pd(0)簇。 Pd(0)活性位点作用于CT的结合并将电子转移至H/H2O形成吸附的原子氢(H•)。 Pd-Fe氢氧化物表面吸附的CT分子通过H•的攻击和直接电子转移不断脱氯形成CH和CH。在实际地下水应用中，CT 被快速去除，CH 和 CH 产率分别达到 24.5 % 和 4.6 % (mol%)。令人鼓舞的是，不完全脱氯产品，包括氯仿和二氯甲烷，即使在 60 分钟后也没有显示出后续反弹的迹象。此外，Pd-Fe氢氧化物还表现出对溶解氧氧化作用的抵抗力，这表明其具有广阔的应用前景。