Cobalt-doped nitrogen-rich covalent organic framework for coupled oxygen evolution and ethylene glycol oxidation toward PET waste upcycling.

Abstract

In electrochemical water splitting, the slow kinetics of the oxygen evolution reaction (OER) continue to be a significant bottleneck. This has prompted the development of alternative anodic oxidation methods that can produce value-added products while requiring less energy. Here, we describe a nitrogen-rich covalent organic framework that functions as an effective electrocatalyst for the ethylene glycol oxidation reaction (EGOR) and OER. It contains coordinated earth-abundant cobalt sites and redox-active moieties. Additionally, the catalyst retains its electrochemical activity when PET hydrolysate is present, demonstrating its suitability for feedstocks derived from plastic and underscoring the possibility of combining waste plastic valorization with different anodic oxidation techniques. Effective catalytic activity in alkaline conditions is made possible by the heteroatom-rich framework with cobalt coordination sites and superior structural stability. With an overpotential of 400 mV needed to achieve the benchmark current density, our organic framework catalyst shows encouraging OER activity. Furthermore, with a faradaic efficiency of ∼97%, it preferentially converts ethylene glycol to formate, exhibiting promising activity toward ethylene glycol oxidation.