Electrocatalytic upcycling of polyethylene terephthalate plastic wastes with hydrogen generation over tremella-like oxygen-deficient NiAl-LDHs microflowers

The electrocatalytic upcycling of polyethylene terephthalate (PET) into value-added chemicals, coupled with hydrogen evolution, presents a promising approach to addressing plastic pollution and clean energy generation. However, achieving both high efficiency and long-term durability remains a significant challenge. To overcome this challenge, we developed tremella-like oxygen-deficient NiAl layered double hydroxides microflowers (NiAl-LDHs-Ov) for efficient valorization of PET and hydrogen production. In the PET-derived ethylene glycol (EG) oxidation, compared with pristine NiAl-LDHs, the NiAl-LDHs-Ov catalyst exhibited an expanded (003) interplanar spacing (0.92 nm), offering more accessible active sites, along with a higher concentration of oxygen vacancies with 5.76 × 10 14 spin g −1 . Thus the NiAl-LDHs-Ov catalyst achieved 94.9 % EG conversion, 91.1 % FA selectivity, and 96.5 % FA Faradaic efficiency at 1.57 V vs. RHE within 3 h, outperforming pristine NiAl-LDHs. A combination of in situ and ex situ techniques revealed that abundant oxygen vacancies serve as Lewis acid sites to significantly facilitate the formation of OH* intermediates, thereby promoting the adsorption of C O bonds in EG and accelerating the desorption of C O bonds in FA. Moreover, the integrated NiAl-LDHs-Ov(+)||FeSi(−) system exhibited outstanding durability, sustaining high performance for over 400 h, outperforming previously reported systems (~100 h). An economic assessment estimated a revenue of approximately $2335.1 per ton of PET processed, highlighting its potential for practical application. This study underscores the critical role of oxygen vacancies in designing efficient non-precious metal catalysts for electrocatalytic upcycling of PET plastic wastes.