Fe-based metal–organic frameworks (MOFs) are popular in activating oxidants e.g·H₂O₂ and persulfate (PS) for degrading recalcitrant organic substances, generally regarded with a simple interfacial efficient iron cycle. This study has revealed that a novel two-steps single-electron transfer mechanism would occur initially to activate the rapid degradation 4-chlorophenol (4-CP) in the MIL-88B(Fe)/H₂O₂ system (88B/H₂O₂ system). The degradation of 4-CP was acidic favorable (pH₀ ≤ 6.0) and could be divided into two reaction stages, i.e., initial lag phase (0–10 min) and following rapid decay phase (10–50 min). In the first stage, H₂O₂ was slowly activated on the surface of 88B to form superoxide radical (O₂^•–), which would lead to the accumulation of the key intermediate hydroquinone (HQ) through reducing 4-CP. Afterwards, HQ could reductively dissolve iron ions which would lead to the subsequent efficient homogeneous Fenton reaction for the rapid oxidation of 4-CP by hydroxyl radical (•OH) in the following rapid decay phase. It was interesting to note that specific aromatic compounds, which would form reductive benzenediols intermediates by O₂^•–, could be efficiently degraded in the 88B/H₂O₂ system. The result of this study is expected to provide a new insight for understanding the catalytic oxidation process based on MOFs, and its application if possible.

铁基金属有机骨架 (MOF) 在活化氧化剂如·H ₂ O ₂和过硫酸盐 (PS) 中很受欢迎，用于降解顽固的有机物质，通常被认为具有简单的界面有效铁循环。该研究表明，最初会出现一种新的两步单电子转移机制，以激活 MIL-88B(Fe)/H ₂ O ₂系统 (88B/H ₂ ) 中的快速降解 4-氯苯酚 (4-CP) O ₂系统）。4-CP 的降解呈酸性（pH ₀  ≤ 6.0），可分为两个反应阶段，即初始滞后阶段（0-10 分钟）和随后的快速衰减阶段（10-50 分钟）。在第一阶段，H ₂ O₂在88B表面缓慢活化形成超氧自由基(O ₂ ^•– )，通过还原4-CP导致关键中间体对苯二酚(HQ)的积累。之后，HQ 可以还原溶解铁离子，这将导致随后的高效均相 Fenton 反应，在随后的快速衰减阶段中，羟基自由基 (•OH) 快速氧化 4-CP。有趣的是，可以通过 O ₂ ^{•–形成还原性苯二醇中间体的特定芳族化合物可以在 88B/H} ₂ O ₂中有效降解系统。这项研究的结果有望为理解基于 MOFs 的催化氧化过程及其应用提供新的见解。