Photothermal Catalytic Polyester Upcycling over Cobalt Single‐Site Catalyst

Abstract Photothermal catalytic conversion of waste plastics into fuels and/or feedstocks using renewable solar energy can achieve solar‐to‐chemical conversion, resource sustainability, and environmental remediation simultaneously. However, the construction of photothermal catalysts with strong light absorption and high catalytic activity remains a great challenge. In this work, integrated cobalt single‐site catalysts (Co SSCs), coupled with strong photothermal conversion, high catalytic activity, and stability, are employed to catalyze the glycolysis of polyesters. The unique coordination‐unsaturated CoO 5 single‐site can coordinate with the carbonyl groups in polyester, thus boosting the nucleophilic addition elimination processes. As a result, the space‐time yield of Co SSCs is an order of magnitude higher than that of general catalysts. In addition, the polyethylene terephthalate (PET) conversion and bis(2‐hydroxyethyl) terephthalate yield in photothermal catalysis are 5.4 and 6.6 times higher than those of thermal catalysis under the same conditions, which are contributed by the localized heating effect. Technical economic analysis shows that the recycling of 10 5 tons of waste PET by photothermal catalysis consumes 146.4 GW·h electrical energy and misses 7.44 × 10 4 tons of CO 2 emission. Therefore, a high‐efficient photothermal catalytic plastic recycling system is of great significance for waste plastic valorization.