Metal-coordinated salen-based conjugated microporous polymers derived Ni/N-doped hollow carbon microtubes for enhanced alkaline oxygen evolution electrocatalysis

Herein, we report a modular strategy for constructing high-performance OER catalysts via the thermal transformation of metal-linked salen-based conjugated microporous polymers (TPE-SAL-Ni CMP), which was prepared through Sonogashira reaction of 1,1,2,2-tetrakis(4-ethynylphenyl)ethene (TPE-T) with OPDI-Ni-2Br into Ni/N co-doped hollow carbon microtubes. The Ni2+ ions coordinated with salen-type ligands (TPE-SAL-Ni CMP) enabled the uniform distribution of the active site. Furthermore, subsequent pyrolysis of TPE-SAL-Ni CMP at 700 °C and 800 °C induced the formation of graphitized carbon frameworks embedded with metallic Ni0 nanoparticles. TPE-SAL-Ni CMP700 displayed a dramatic reduction in charge-transfer resistance (R_ct), an optimized Tafel slope of 93 mV dec−1, and an exceptionally low overpotential of 419 mV at 10 mA cm−2. Structural and spectroscopic analyses revealed the coexistence of Ni0 and Ni2+–N species, which synergistically enhanced electron transport and reaction kinetics. In addition, TPE-SAL-Ni CMP700 developed a hollow tubular architecture that facilitated electrolyte diffusion and enhanced active site accessibility.