Heterocyclic Modulated Electronic States of Alkynyl‐Containing Conjugated Microporous Polymers for Efficient Oxygen Reduction

Abstract

AbstractThe oxygen reduction reaction (ORR) is a key process in green energy conversion technology. Heteroatom doping has been proven to be a prospective strategy to prepare metal‐free carbon‐based electrocatalysts, but such methods often suffer from uncontrollable catalyst frameworks and imprecise active sites. Herein, an organic heterocyclic strategy is adopted to modulate the charge redistribution of alkynyl‐containing conjugated microporous polymers (CMPs) by introducing varied five‐membered heterocyclic structures. Among these CMPs, the S, 2N‐containing thiadiazole heterocyclic molecule (CMP‐Tdz) with carbonized alginate materials (CCA) displays a remarkable quasi‐four‐electron‐transfer ORR pathway, exhibiting an excellent half‐wave potential (E1/2) of 0.77 V, coupled with superior methanol tolerance and electrochemical stability, which are among the highest performance in the metal‐free organic catalytic material systems. Density functional theory calculations prove that the high catalytic performance of these catalysts originates from the sp‐hybridized C atom (site–2) which is activated by their adjacent heterocyclic structures. Importantly, the five‐membered heterocyclic structures can also modulate the local charge distribution, and increase dipole moment, with significantly improved catalytic kinetics. This incorporation of chemically designed heterocyclic‐containing alkynyl‐CMPs provides a new approach to developing efficient metal‐free carbon‐based electrocatalysts for fuel cells.