Developing efficient and eco-friendly catalysts for selective degradation of waste polyethylene terephthalate (PET) is critical to the circular economy of plastics. Herein, we report the first monatomic oxygen anion (O À )-rich MgOÀ Ni catalyst based on a combined theoretical and experimental approach, which achieves a bis(hydroxyethyl) terephthalate yield of 93.7 % with no heavy metal residues detected. DFT calculations and electron paramagnetic resonance characterization indicate that Ni 2 + doping not only reduces the formation energy of oxygen vacancies, but also enhances local electron density to facilitate the conversion of adsorbed oxygen into O À . O À plays a crucial role in the deprotonation of ethylene glycol (EG) to EG À (exothermic by À 0.6 eV with an activation barrier of 0.4 eV), which is proved effective to break the PET chain via nucleophilic attack on carbonyl carbon. This work reveals the potential of alkaline earth metal-based catalysts in efficient PET glycolysis.

The Cover Feature shows the glycolysis of waste polyethylene terephthalate (PET) catalyzed by Ni2+‐doped MgO, which exhibits excellent performance with a bis(hydroxyethyl) terephthalate yield of 93.7 %. Ni2+ doping is found critical to the generation of oxygen vacancies and monatomic oxygen anions, which deprotonate ethylene glycol to break the PET chain via nucleophilic attack. More information can be found in the Research Article by Y. Lin et al.

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