An industrially viable catalyst for heterogeneous catalytic ozonation (HCO) in water purification requires the characteristics of good dispersion of active species on its surface, efficient electron transfer for ozone decay, and maximum active species utilization. While metal–organic frameworks (MOFs) represent an attractive platform for HCO, the metal nodes in the unmodified MOFs exhibit low catalytic activity. Herein, we present a perfluorinated Fe–MOF catalyst by substituting H atoms on the metalated ligands with F atoms (termed 4F-MIL-88B) to induce structure evolution. The Lewis acidity of 4F-MIL-88B was enhanced via the formation of Fe nodes, tailoring the electron distribution on the catalyst surface. As a result of catalyst modification, the rate constant for degradation of the target compounds examined increased by ∼700% compared with that observed for the unmodified catalyst. Experimental evidence and theoretical calculations showed that the modulated polarity and the enhanced electron transfer between the catalyst and ozone molecules contributed to the adsorption and transformation of O₃ to ^•OH on the catalyst surface. Overall, the results of this study highlight the significance of tailoring the metalated ligands to develop highly efficient and stable MOF catalysts for HCO and provide an in-depth mechanistic understanding of their structure–function evolution, which is expected to facilitate the applications of nanomaterial-based processes in water purification.

中文翻译：

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用于水净化的定制金属有机框架：用于增强多相催化臭氧化的全氟化 Fe-MOF


工业上可行的用于水净化中的非均相催化臭氧化 (HCO) 的催化剂需要具有活性物质在其表面良好分散、有效的臭氧衰减电子转移以及最大程度地利用活性物质的特性。虽然金属有机框架 (MOF) 是 HCO 的一个有吸引力的平台，但未改性的 MOF 中的金属节点表现出较低的催化活性。在此，我们提出了一种全氟化 Fe-MOF 催化剂，通过用 F 原子取代金属配体上的 H 原子（称为 4F-MIL-88B）来诱导结构演化。 4F-MIL-88B 的路​​易斯酸性通过 Fe 节点的形成而增强，从而调整催化剂表面上的电子分布。催化剂改性的结果是，与未改性催化剂相比，所检测的目标化合物的降解速率常数增加了约 700%。实验证据和理论计算表明，极性的调制和催化剂与臭氧分子之间电子转移的增强有助于O ₃ 在催化剂表面吸附并转化为 ^• OH。总的来说，这项研究的结果强调了定制金属配体以开发高效稳定的 HCO MOF 催化剂的重要性，并提供对其结构-功能演化的深入机理理解，这有望促进纳米材料的应用。水净化的基础工艺。