Synergistic Effect of Bimetallic Spinel CuFe ₂ O ₄ Nanoparticles in a Bipyridine-Based Covalent Organic Framework for Robust Water Oxidation

Covalent Organic Frameworks (COFs), as crystalline and porous materials, have been investigated for OER applications, but their OER efficiency remains lower due to the absence of active catalytic sites. COF composites with metallic nanostructures tend to demonstrate high electrocatalytic activity because of their enhanced conductivity, high charge mobility, and stability. Herein, we conceptualized the in situ synthesis of a highly active and stable COF composite (Py-BPy-COF@30%CFO) by incorporating a varied ratio of spinel bimetallic copper ferrite (CFO) into a bipyridine-based COF. The spinel bimetallic system was perfectly embedded into the COF’s pore network owing to the coordination ability of the bipyridine moiety. Each COF composite was systematically evaluated for OER applications, and the optimized Py-BPy-COF@30%CFO delivered high OER performance at a current density of 10 mA/cm 2 with a low overpotential of 379 mV and high stability over 40 h. The synergy between the metallic spinel CuFe 2 O 4 (CFO) catalyst and COF leads to a high catalytic surface, abundant active sites, and improved conductive and redox-active properties, resulting in enhanced charge mobility and mass transfer for OER activity. It developed COF composites as highly efficient and stable OER catalysts, superior to pristine COFs and bimetallic systems. This study provides insights into the design of efficient and durable COF-based electrocatalysts for sustainable energy applications.