Molecular complex inspired design of an efficient copper(II)-containing robust porous polymers for electrochemical water oxidation

•Three copper-containing polymer networks TpBpy-CuX (X = 1, 3, 5) were carefully prepared.•Cyclic voltammetry (CV) studies and electrochemical impedance spectroscopy (EIS) measurements highlight the superior efficiency of TpBpy-Cu3 in facilitating charge transfer processes and the water oxidation performance.•CV confirmed the similar pH-dependency behavior to their molecular counterpart, illustrating the catalysis information of molecular catalysts is instructive in designing metalated COF materials and understanding their catalysis behavior.•The comparison of SEM, TEM, FT-IR, CV, and LSV before and after CPE verified the reusability and stability of TpBpy-CuX at pH 12.4. Homogeneous copper-bipyridine complexes have been reported as effective catalysts for water oxidation, demonstrating significant potential as alternatives to precious metal-based complexes. However, these complexes face long-term stability and product separation challenges similar to many homogeneous catalysts. Meanwhile, recent studies have underscored the potential of metalated polymer networks, which integrate the structural advantages of polymers with the functional benefits of metal species, making them highly attractive for various applications. Herein, we integrated copper-bipyridine units into porous polymer networks to overcome the limitations of copper-bipyridine complexes. We prepared a series of copper-incorporated polymers (TpBpy-Cux) for electrochemical water oxidation. The electrochemical properties of these polymers were tuned by varying the copper content, with TpBpy-Cu3 presenting the best performance among the samples studied. TpBpy-Cu3 demonstrated a low Tafel slope of 69 mV/decade, achieved a high Faradaic efficiency (FE) of 94 %, and exhibited exceptional stability over 1000 cyclic scans. This study offers insights into the design and optimization of metal-incorporated porous polymer networks building on the foundational understanding of their molecular counterparts for advanced catalytic applications. In this study, we synthesized a series of copper-incorporated porous polymer networks (TpBpy-CuX) using Schiff base condensation, employing 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (Tp), benzidine (Bzd), and (bpy-NH2)Cu(OH)2 (Cu-bpy) as building blocks. The structural properties of these materials were characterized through SEM, TEM, EDX, and XPS. Electrochemical evaluations identified TpBpy-Cu3 as the optimal catalyst, exhibiting a low onset potential, high water