Kang Yuyang, Gu Zhenao, Ma Baiwen, Zhang Wei, Sun Jingqiu, Huang Xiaoyang, Hu Chengzhi, Choi Wonyong, Qu Jiuhui
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2023 Oct 18;14(1):6590. doi: 10.1038/s41467-023-42224-3.
Electrocatalytic oxidation offers opportunities for sustainable environmental remediation, but it is often hampered by the slow mass transfer and short lives of electro-generated radicals. Here, we achieve a four times higher kinetic constant (18.9 min) for the oxidation of 4-chlorophenol on the reactive electrochemical membrane by reducing the pore size from 105 to 7 μm, with the predominate mechanism shifting from hydroxyl radical oxidation to direct electron transfer. More interestingly, such an enhancement effect is largely dependent on the molecular structure and its sensitivity to the direct electron transfer process. The spatial distributions of reactant and hydroxyl radicals are visualized via multiphysics simulation, revealing the compressed diffusion layer and restricted hydroxyl radical generation in the microchannels. This study demonstrates that both the reaction kinetics and the electron transfer pathway can be effectively regulated by the spatial confinement effect, which sheds light on the design of cost-effective electrochemical platforms for water purification and chemical synthesis.
电催化氧化为可持续环境修复提供了机遇，但它常常受到传质缓慢和电生成自由基寿命短的阻碍。在此，我们通过将孔径从105微米减小到7微米，使4-氯苯酚在反应性电化学膜上氧化的动力学常数提高了四倍（18.9分钟），主要机制从羟基自由基氧化转变为直接电子转移。更有趣的是，这种增强效应在很大程度上取决于分子结构及其对直接电子转移过程的敏感性。通过多物理场模拟可视化了反应物和羟基自由基的空间分布，揭示了微通道中压缩的扩散层和受限的羟基自由基生成。这项研究表明，反应动力学和电子转移途径都可以通过空间限制效应得到有效调控，这为设计用于水净化和化学合成的经济高效电化学平台提供了启示。
