MOF-based catalytic systems for PFAS degradation: mechanisms, composite design and future challenges

Per- and polyfluoroalkyl substances (PFAS) represent one of the most persistent classes of environmental contaminants, their exceptional carbon–fluorine bond strength rendering them recalcitrant to conventional treatment technologies. Metal organic frameworks (MOFs), with their precisely engineered pore architectures, tunable surface chemistry, and multifunctional active sites, have emerged as transformative platforms for both adsorptive capture and catalytic degradation of PFAS. This review provides a comprehensive and critical analysis of MOF-based catalytic systems for PFAS degradation, encompassing photocatalytic, Fenton-like, reductive, and synergistic mechanisms. The roles of metal node identity, organic linker design, and pore geometry in governing degradation pathways are systematically examined. The review further evaluates composite strategies including MOF@metal oxide heterojunctions, MOF@carbon hybrids and bi- and tri-metallic MOF architectures that extend light absorption, enhance charge carrier separation, and improve structural stability under realistic environmental conditions. Particular emphasis is placed on quantifying the performance gap between these multifunctional composites, pristine single-metal MOFs, and commercial adsorbents. This gap is assessed using defluorination and mineralization rather than parent-compound removal. On this basis, the review identifies the polymetallic and reductive strategies most likely to overcome the persistent short-chain PFAS bottleneck. Key operational parameters including pH, light intensity, co-existing ions, PFAS chain length and catalyst dosage are critically evaluated. Current challenges including water instability, low mineralization efficiency, metal leaching, and insufficient short-chain PFAS removal are identified and forward-looking research priorities are proposed, including AI-guided framework design, continuous-flow reactor engineering, and electrocatalytic coupling strategies. This work establishes a comprehensive framework for the rational design of next-generation MOF-based systems targeting complete PFAS mineralization.