Co-based metal–organic frameworks synthesized from poly(ethylene terephthalate) waste plastics for rapid detection of p-phenylenediamine

Abstract

The environmental issues and health problems of waste plastics have attracted remarkable attention. It is quite important to convert waste plastics into high value-added electrochemical materials. Herein, four kinds of Co-based metal–organic frameworks (CoMOFs) were synthesized from poly(ethylene terephthalate) plastic, and their electrochemical applications were examined. A mixture of N,N-dimethylformamide (DMF) and H₂O was used as the solvent, and hydrothermal reaction was employed. It is found that the surface area and porous structure of CoMOFs are closely related to the volume ratio of DMF/H₂O. As a result, the prepared CoMOFs exhibit different catalytic enhancement activities toward the oxidation of p-phenylenediamine (PPD). Based on the solvent-controlled sensing performance of CoMOFs, a highly sensitive and rapid detection method has been developed for PPD, with a linear range from 0.05 to 8.0 μM. The detection limit was 45 nM, and the practical application in hair dye samples was successfully demonstrated.