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Recently, the research group led by Professor Huang Minghua from the School of Materials Science and Engineering at Ocean University of China has made significant progress in the field of electrocatalytic plastic upgrading and recycling; a related research paper was published in ACS Catalysis, a top international journal in the field of catalysis. Petroleum-based polyethylene terephthalate (abbreviated as PET) is a high-molecular-weight thermoplastic material that serves as an important basic material in modern industry and daily life. However, PET is generally difficult to degrade under natural conditions after being discarded, becoming a major source of white pollution and posing a serious threat to ecological environment safety and human health. Electrochemical methods powered by renewable energy can not only oxidize ethylene glycol, the hydrolysis product of PET, into high-value chemicals, but also facilitate the hydrogen evolution reaction at the cathode, thereby reintroducing underutilized carbon resources into the economic cycle and contributing to the sustainable development of global carbon neutrality. However, the adsorption mechanism of the key reaction intermediates during the ethylene glycol oxidation reaction remains unclear, which constitutes a key scientific issue for improving the reaction efficiency and selectivity. To address these challenges, the research group led by Professor Huang Minghua successfully synthesized amorphous CoNiOOH/NF and CoNiOOH-Ni3S2/NF with an amorphous/grain boundary interface by simply adjusting the electrochemical activation time. These materials were used as model catalysts to explore the potential mechanism for the conversion of ethylene glycol into formates. Detailed characterization and theoretical calculations show that, compared to amorphous CoNiOOH/NF, the interaction at the amorphous/grain boundary in CoNiOOH-Ni3S2/NF can adjust the electronic structure, causing the center of the d-band to shift upward toward the Fermi level. This leads to a significant enhancement in the adsorption capacity for ethylene glycol and OH groups; such enhanced OH adsorption is crucial for promoting the breaking of C–C bonds and subsequent cascade dehydrogenation steps. The main reaction pathway was determined through in-situ electrochemical infrared absorption spectroscopy and theoretical calculations; it was found that the formation of the final product, formate, occurs primarily through the breaking of the C–C bond in glycolic acid followed by subsequent oxidation. It is worth noting that CoNiOOH-Ni3S2/NF achieved an industrial-grade current density of 500 mA cm⁻² at an ultra-low potential of 1.45 V, with a Faradaic efficiency as high as 96.6% and a formate production rate of 3.14 mmol cm⁻² h⁻¹. The study also designed a practical two-electrode flow electrolyzer, which exhibited excellent catalytic activity and stability, successfully converting 6.3 g of ethylene glycol terephthalate feedstock into 4.97 g of terephthalic acid and 4.83 g of potassium dimethanoate. By precisely controlling the adsorption of key intermediates at the active sites and gaining a deeper understanding of the reaction pathways, this study provides important theoretical guidance for designing efficient non-precious metal heterojunction catalysts for the electrochemical upgrading of PET plastics. This research was funded by projects such as the National Natural Science Foundation of China, the Major Basic Research Projects of the Shandong Provincial Natural Science Foundation, and funds provided to central universities; Ocean University of China was the sole institution to carry out this work. The first author of this paper is Sun Jinyong, a doctoral student in the class of 2022.