Defective Layered Double Hydroxide Nanosheet Boosts Electrocatalytic Hydrodechlorination Reaction on Supported Palladium Nanoparticles

作者：Xiaoshu Lv, Kanxin Jiang, Hong Wu, Liang Ao, Lin Hu, Xiaoyu Li, Fei Shen, Li Shi, Fan Dong, Guangming Jiang · 发表于：ACS ES&T Water · 年份：2022 · DOI：10.1021/acsestwater.2c00205 · 被引用次数：31 · 研究领域：Environmental remediation with nanomaterials、Nanomaterials for catalytic reactions、Advanced oxidation water treatment

Electrocatalytic hydrodechlorination on Pd, utilizing the H + of H 2 O as hydrogen sources, represents a promising technology to detoxify the chlorinated organic pollutants (COPs) in water bodies. However, Pd alone affords limited activity due to its low efficacy in H 2 O disassociation and the poor mass diffusion of COPs that are commonly of low concentrations in the environment. Herein, we demonstrate that arming Pd with OH – vacancy-bearing NiAl-layered double hydroxide nanosheets (Pd/Ni x Al 100– x -LDH-OH v ) can significantly improve its performance, benefiting from the enhanced H 2 O disassociation at OH v and the facilitated C–Cl cleavage on the supported Pd nanoparticles. Al 3+ is also indispensable because it promotes the formation and regeneration of OH v, but an overload will reduce the number of accessible OH v and weaken its function. Pd/Ni 67 Al 33 -LDH-OH v with the optimal Ni/Al ratio delivers a peak specific activity of 0.53 min –1 m –2 and mass activity of 6.54 min –1 g –1 Pd in treating 50.0 mg L –1 2,4-dichlorophenol (2,4-DCP, a probe COP) at −0.25 V versus RHE, outperforming most of the reported catalysts. To address the mass diffusion issue, Pd/Ni 67 Al 33 -LDH-OH v is integrated into a customized continuous-flow membrane cell. When fed a dilute wastewater (20.4 mg L –1 ), the system affords a 2,4-DCP removal rate of 3.75 g 2,4-DCP g catalyst –1 h –1 and faradaic current efficiency of 42.6%, which is 3.2 and 4.0 times that obtained in a traditional batc...