Tunable reconstruction of metal-organic frameworks for advanced electrocatalytic degradation of antibiotics: Key role of structural defects and pollutant properties

Abstract

Although metal-organic frameworks (MOFs) catalysts are appealing for removing emerging contaminants, they are significantly restricted by the activity-stability trade-off effect. This study develops a facile and sustainable strategy to realize the synchronous promotion of stability and activity by utilizing the metastable property of UiO-66 with optimal defect concentration to in-situ reconstruct into more stable and active ZrOOH@UiO-66 heterojunction under working conditions. The crucial role of structural defects and pollutant properties in controlling MOFs reconstruction was unveiled by tracking dynamic structure evolution during electrocatalytic degradation of antibiotics. The mechanism is the selective oxidation of exposed metal active sites on defective UiO-66 during electrocatalysis, forming well-dispersed ZrOOH with rich oxygen vacancies that protected MOFs and reduced activation energy for •OH and •O₂^– radicals generation. Additionally, lower ionization potential and stronger adsorption of antibiotics restricted reconstruction of defective UiO-66 by inhibiting electron transfer and occupying reconstruction site. Besides, the reconstructed UiO-66 electrocatalytic membrane presented high stability, removing approximately 90 % of tetracycline with efficient self-cleaning and low energy consumption (0.4 mW•h/m³) in surface water remediation over 200 h. This strategy is also feasible for other carboxylate-based MOFs, which provides the guidance for MOFs-based catalysts in emerging contaminants removal from complex water matrices.