Highly selective depolymerization of polyethylene terephthalate plastic via Au/attapulgite dual-site synergy

The chemical recycling of waste polyethylene terephthalate (PET) into high-value terephthalic acid (TPA) under mild conditions remains a significant challenge. Herein, we construct a dual-active-site Au/ATP catalyst via electronic metal-support interactions (EMSI) by supporting Au on inexpensive attapulgite (ATP). Under optimal conditions (200 °C, 1 MPa Ar, 4 h), this catalyst achieves near-complete conversion of PET with a terephthalic acid (TPA) yield of 91.76 ± 1.65%, and is also effective for actual waste plastic bottle flakes. The EMSI stabilizes Au nanoparticles, modulates Lewis acidity to suppress side reactions, and enables selective ester-bond cleavage without affecting the benzene ring or CC bonds. X-ray photoelectron spectroscopy (XPS), work-function analysis and density functional theory (DFT) calculations show that the EMSI effect drives electron transfer from Au to ATP, generating Au^δ+ species. These species can effectively polarize the CO bond to generate an electron-deficient intermediate. Meanwhile, ATP provides an adsorption and activation platform for H₂O, promoting the generation of nucleophilic *OH. The synergy of these two sites enables highly performance depolymerization. This work provides a sustainable strategy for polyester chemical recycling and the value-added upgrading of low-grade mineral resources.