Multifunctional Fe, N Co-Doped Microporous Carbons Derived from Conjugated Microporous Polymer Containing Tetraphenylethylene and Iron-Chelated 1,10-Phenanthroline Units as Platforms for CO2 Uptake, Supercapacitor, and Oxygen Evolution Reaction

Abstract The development of multifunctional microporous carbons for integrated electrochemical energy storage, CO2 capture, and oxygen evolution electrocatalysis (OEECs) is an attractive approach for sustainable energy applications. In this work, Fe/N codoped porous carbons (TPE-PhenFe-CMP-700 and TPE-PhenFe-CMP-800) were synthesized from a tailor-made conjugated microporous polymer (CMP) precursor prepared through a Sonogashira–Hagihara cross-coupling reaction between an ethynyl-functionalized tetraphenylethylene (TPE-T) linker and an iron-chelated 3,8-dibromo-1,10-phenanthroline (Phen-Fe-2Br) monomer. The molecularly engineered precursor enables well-distributed Fe and N species throughout the carbon framework after carbonization. Among the materials obtained, TPE-PhenFe-CMP-800 exhibits a SBET of 411 m2 g–1 and a well-developed porous graphitic structure. The synergistic combination of porosity-enhanced graphitic carbon networks and the presence of Fe–N active sites endows the material with outstanding multifunctional performance. The TPE-PhenFe-CMP-800 delivers high specific capacitance (Cs) of 892 F g–1 at 0.5 A g–1, in a three-electrode supercapacitor (SCs) configuration, together with excellent CO2 adsorption of 4.01 mmol g–1 at 273 K. Furthermore, TPE-PhenFe-CMP-800 exhibits outstanding OER electrocatalytic activity, demonstrating an overpotential as low as 530 mV to reach 10 mA cm–2, along with a favorable Tafel slope of 82 mV dec–1 and an extensive electrochemically active surface area (ECSA) of 76 cm2. These results demonstrate that molecular engineering of CMP precursors provides an effective strategy for constructing multifunctional Fe/N codoped porous carbons, offering a versatile platform for advanced electrochemical energy storage, CO2 capture, and electrocatalytic applications.