A Pd/MnO₂/Ni foam electrode with hierarchical structure was synthesized via electrodeposition for efficient electrocatalytic hydrodechlorination. Compared with the ordinary Pd/Ni foam electrode, the introduction of MnO₂ greatly enhanced the catalytic reactivity and reduced the dose of precious metal Pd. Only a quarter of Pd was required for the Pd/MnO₂/Ni foam compared to the Pd/Ni electrode to achieve complete dechlorination of 2,4-dichlorobenzoic acid (2,4-DCBA) within 120 min. Various characterizations suggested that MnO₂ covered the surface of the Ni foam and increased the specific surface area of the electrode, while Pd nanoparticles were subsequently deposited on MnO₂. The atomic H^∗-based indirect dechlorination was the dominant pathway while only approximately 13% of 2,4-DCBA was removed by direct electron transfer. Atomic H^∗ adsorbed on Pd acted as the key active species for the dechlorination of 2,4-DCBA by the Pd/MnO₂/Ni foam electrode in this study. The introduction of MnO₂ would promote the water dissociation and the hydrogen evolution reaction, and provide Pd with more atomic H^∗. Pd/MnO₂/Ni foam exhibited good stability and reusability according to the XPS spectra and consecutive electrocatalytic experiments, which suggested its long-term potential for efficient removal of chlorinated contaminants. This work demonstrated a new strategy to design efficient electrocatalysts with less precious metal.

通过电沉积合成了具有分层结构的Pd / MnO ₂ / Ni泡沫电极，用于高效电催化加氢脱氯。与普通的Pd / Ni泡沫电极相比，MnO ₂的引入大大提高了催化活性，减少了贵金属Pd的用量。与Pd / Ni电极相比，Pd / MnO ₂ / Ni泡沫仅需要四分之一的Pd，即可在120分钟内实现2,4-二氯苯甲酸（2,4-DCBA）的完全脱氯。各种表征表明，MnO ₂覆盖了Ni泡沫的表面并增加了电极的比表面积，而Pd纳米颗粒随后沉积在MnO _2上。原子H ^∗基的间接脱氯是主要途径，而直接电子转移仅除去了约13％的2,4-DCBA。在本研究中，吸附在Pd上的原子H ^＊是Pd / MnO ₂ / Ni泡沫电极对2，4-DCBA脱氯的关键活性物质。MnO ₂的引入将促进水的离解和氢的分解反应，并为Pd提供更多的原子H ^＊。Pd / MnO ₂根据XPS光谱和连续的电催化实验，/ Ni泡沫材料显示出良好的稳定性和可重复使用性，这表明其长期有效地去除氯化污染物的潜力。这项工作展示了一种设计较少贵金属的高效电催化剂的新策略。