Vacancy-rich NiFe-LDH/carbon paper as a novel self-supporting electrode for the electro-Fenton degradation of polyvinyl chloride microplastics

文章亮点介绍：用电化学方法将聚氯乙烯（PVC）升级再造为高价值小分子，是减轻塑料污染的可持续战略。本文开发了一种具有丰富空位的成本效益高的自支撑电极，即在碳纸表面原位生长的NiFe层状双氢氧化物纳米阵列（表示为NiFe_V-LDH/CP），用于PVC微塑料（MP）的电芬顿降解。NiFe_V-LDH 催化剂通过双电子氧还原反应（2e^- ORR）产生 H₂O₂ 的选择性高达76%。密度泛函理论（DFT）计算显示，与原始 NiFeZn-LDH 相比，富集空位的 NiFe_V-LDH在决定速率步骤（*H₂O₂ 解吸）上的能量势垒降低了。系统研究了空位浓度、反应温度和PVC微塑料初始浓度的影响。在优化条件下，NiFe_V -LDH/CP电极通过直接阴极还原和羟基自由基氧化对PVC微塑料表现出优异的降解性能。这项工作表明，使用基于LDH的自支撑电极的电芬顿技术是一种有前景且环保的废塑料处理方法。

Electrochemically upcycling polyvinyl chloride (PVC) into high-value small molecules represents a sustainable strategy for mitigating plastic pollution. Herein, a cost-effective self-supporting electrode with abundant vacancies, i.e., NiFe-layered double hydroxide nanoarrays in-situ grown on the surface of carbon paper (denoted as NiFe_V-LDH/CP), is developed for the electro-Fenton degradation of PVC microplastics (MPs). The NiFe_V-LDH catalyst shows a high selectivity of 76 % towards H₂O₂ production via two-electron oxygen reduction reaction (2e^- ORR). Density functional theory (DFT) calculations reveal that the energy barrier of rate-determining step (*H₂O₂ desorption) decreases over the vacancy-enriched NiFe_V-LDH related to the pristine NiFeZn-LDH. The influence of vacancy concentration, reaction temperature and initial concentration of PVC MPs were systematically investigated. Under optimized conditions, the NiFe_V-LDH/CP electrode exhibits an outstanding degradation performance of PVC MPs via direct cathodic reduction and oxidation by hydroxyl radicals. This work demonstrates that the electro-Fenton technology using LDH-based self-supporting electrodes is a promising and environmentally-friendly approach for waste plastic treatment.

利用水热合成法，将三金属LDH原位生长在碳纸上，再进行碱溶，形成富有金属空位的NiFe-LDH复合材料，即NiFe_V-LDH/CP。用于PVC微塑料（MP）的电芬顿降解。

期刊名称：Journal of Hazardous Materials

中科院分区：环境科学与生态学一区top

发表日期: 2024年12月9日

文章链接: https://doi.org/10.1016/j.jhazmat.2024.136797

作者列表: Yuan Wang, Haihong Zhong^*, Qianqian Xu, Miao Dong, Jianxin Yang, Weiting Yang^*,Yongjun Feng^*, Zhong-Min Su

期刊信息: J. Hazard. Mater. 2025, 485, 136797.