Modulating Oxygen Reduction Activity in Chalcogenophene-Incorporated Organic Electrocatalysts through Main-Group...

Organic small molecules (OSMs) with well-defined structures are crucial integral components of cathode catalysts for fuel cells. Despite the acknowledged potential of heteroatom doping to enhance the catalytic performance of metal-free carbon-based catalysts, there exists a notable gap in conducting molecular structure and catalytic activity, particularly under the premise of maintaining a constant molecular skeleton and with a clear molecular structure. Herein, the charge distribution is modulated by introducing different chalcogens into the same molecular skeleton through main-group engineering. Among these OSMs, the Se-containing small molecule OSM-Se combined with carbonized calcium alginate exhibits a notable quasi-four-electron-transfer oxygen reduction reaction pathway, displaying a superior half-wave potential (E_1/2) of 0.73 V, accompanied by outstanding electrochemical stability. Density functional theory calculations demonstrate that Se-containing small molecules can enhance the capabilities of catalysts in adsorbing and dissociating oxygen molecules, and contribute to reducing the reaction barrier of the oxygen reduction reaction. This study presents a straightforward yet highly effective approach for metal-free carbon-based OSM electrocatalysts.