Shanghai Key Laboratory of Chemical Assessment and Sustainability, Key Laboratory of Yangtze River Water Environment, School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Environ Sci Technol. 2022 Oct 4;56(19):13740-13750. doi: 10.1021/acs.est.2c03673. Epub 2022 Sep 21.
Shifting four-electron (4e) oxygen reduction in fuel cell technology to a two-electron (2e) pathway with traditional iron-carbon electrodes is a critical step for hydroxyl radical (HO) generation. Here, we fabricated iron-carbon aerogels with desired dimensions (e.g., 40 cm × 40 cm) as working electrodes containing atomic Fe sites and FeC subnanoclusters. Electron-donating FeC provides electrons to FeN through long-range activation for achieving the ideal electronic configuration, thereby optimizing the binding energy of the *OOH intermediate. With an iron-carbon aerogel benefiting from finely tuned electronic density, the selectivity of 2e oxygen reduction increased from 10 to 90%. The resultant electrode exhibited unexpectedly efficient HO production and fast elimination of organics. Notably, the kinetic constant for sulfamethoxazole (SMX) removal is 60 times higher than that in a traditional iron-carbon electrode. A flow-through pilot device with the iron-carbon aerogel (SA-FeNCA) was built to scale up micropolluted water decontamination. The initial total organic carbon (TOC) value of micropolluted water was 4.02 mg L, and it declined and maintained at 2.14 mg L, meeting the standards for drinking water quality in China. Meanwhile, the generation of emerging aromatic nitrogenous disinfection byproducts (chlorophenylacetonitriles) declined by 99.2%, satisfying the public safety of domestic water. This work provides guidance for developing electrochemical technologies to satisfy the flexible and economic demand for water purification, especially in water-scarce areas.
将燃料电池技术中的四电子（4e）氧还原反应转变为传统铁碳电极的两电子（2e）途径，对于生成羟基自由基（HO）至关重要。在此，我们制备了具有所需尺寸（例如，40 cm × 40 cm）的铁碳气凝胶作为工作电极，其中包含原子 Fe 位点和 FeC 亚纳米簇。供电子 FeC 通过远程活化为 FeN 提供电子，以达到理想的电子构型，从而优化*OOH 中间体的结合能。由于铁碳气凝胶受益于精细调整的电子密度，2e 氧还原的选择性从 10%提高到 90%。由此产生的电极表现出出乎意料的高效 HO 生成和有机物的快速去除。值得注意的是，磺胺甲恶唑（SMX）去除的动力学常数比传统铁碳电极高 60 倍。带有铁碳气凝胶（SA-FeNCA）的流通式中试设备用于扩大微污染水的净化规模。微污染水的初始总有机碳（TOC）值为 4.02 mg L，下降并保持在 2.14 mg L，符合中国饮用水质量标准。同时，新兴芳香含氮消毒副产物（氯代苯乙腈）的生成减少了 99.2%，满足了国内用水的公共安全需求。这项工作为开发满足水净化灵活和经济需求的电化学技术提供了指导，特别是在水资源匮乏的地区。
