MOF Catalysts for Plastic Depolymerization.

Depolymerization is a promising solution to address the escalating global plastic waste crisis, as a key enabler for emerging technologies in chemical upcycling and closed-loop recycling of plastics. By virtue of their unparalleled bottom-up designability for structural control, stability, reactivity, and compatibility with catalytically-active metal nanoparticles and enzymes, MOFs have enormous potential as an emerging class of porous heterogeneous catalysts for plastics depolymerization. Herein, we highlight key considerations and advances in MOF catalyst development and design for a range of depolymerization reactions, including alcoholysis, hydrogenolysis, pyrolysis, photocatalytic oxidation, and enzymatic hydrolysis. Other than enabling MOFs to efficiently depolymerize the most abundant plastics in production today, including those with unreacted C─C backbones (e.g., polyolefins) and polymers with cleavable backbone linkages (e.g., polyesters), their versatility also extends to emerging applications in microplastic capture and degradation from wastewater. These unique properties of MOFs position them as potentially scalable and reusable heterogeneous catalysts that can complement existing inorganic catalysts for practical depolymerization.