Two-Dimensional Redox-Active Porphyrin-Based Covalent Organic Polymer for Selective H ₂ O ₂ Electrosynthesis toward Efficient Congo Red Degradation

Direct electrosynthesis of hydrogen peroxide (H 2 O 2 ) via the oxygen reduction reaction (ORR) is a green and safe alternative to the conventional anthraquinone process. Here, we report a functionalized two-dimensional redox-active cationic porphyrin-based covalent organic polymer (cpCOP) used directly as a low-cost, pyrolysis-free ORR electrocatalyst for H 2 O 2 production. Its performance was further enhanced by coordinating cobalt ions to the porphyrin pyrrole nitrogen (Co-cpCOP), leading to an improved ORR activity and selectivity. Co-cpCOP exhibits an onset potential of 0.76 V vs RHE with 98% H 2 O 2 selectivity, outperforming metal-free cpCOP (0.65 V vs RHE, 77%). When employed as a cathode catalyst in electrolyzers, Co-cpCOP achieved high H 2 O 2 production rates of 233.4–983.4 mmol h –1 g –1 at 0.35–0.65 V vs RHE. The generated H 2 O 2 was successfully applied for the degradation of the textile dye Congo red.