Copper Oxide-Decorated Zinc Metal–Organic Framework as a Catalyst for Efficient Methanolysis of PET Plastic Waste

Abstract

Plastic upcycling into value-added chemicals is an important approach toward reducing environmental pollution and achieving a circular plastic economy. Herein, a CuO-loaded Zn-MOF (CuO@Zn-MOF) nanohybrid was synthesized and employed as an efficient heterogeneous catalyst for the methanolytic depolymerization of polyethylene terephthalate (PET) into dimethyl terephthalate (DMT). The structural and physicochemical properties of the CuO@Zn-MOF were characterized using ATR-IR, BET, TGA, PXRD, FESEM, HRTEM, EDAX, DLS, and XPS analyses, which confirms the successful incorporation of CuO within the porous Zn-MOF framework. The CuO@Zn-MOF nanohybrid exhibited excellent catalytic performance toward PET methanolysis, affording 93% DMT within 8 h under optimized reaction conditions (catalyst amount, 30 mg, and temperature, 160 °C) as confirmed by ATR-IR, 1H and 13C NMR spectroscopy, and GC-MS analysis. The enhanced catalytic activity of the nanohybrid was attributed to the cooperative role of CuO active sites and the porous Zn-MOF framework, which facilitates efficient substrate adsorption and catalytic transformation. Furthermore, the catalyst demonstrated excellent structural stability and recyclability over multiple catalytic cycles, highlighting its potential as an efficient catalyst for PET plastic upcycling.