<i>In Situ</i> Construction of Bifunctional N-Doped Carbon-Anchored Co Nanoparticles for OER and ORR

Abstract

Designing highly active and more durable oxygen electrocatalysts for regenerative metal-air batteries and water splitting is of practical significance. Herein, an advanced Co/N-C-800 catalyst composed of abundant Co-N_<i>x</i> structures and carbon defects derived from cobalt phthalocyanine is synthesized. Remarkably, this catalyst exhibits favorable catalytic performance toward the oxygen evolution reaction (OER) with a receivable overpotential of 274 mV in an alkaline medium achieving a current density of 10 mA cm^-2 and a Tafel slope of 43.6 mV decade^-1, outperforming the commercial RuO₂ catalyst. It further displays a high half-wave potential (0.82 V) for the oxygen reduction reaction in 0.1 M KOH. Theoretical calculations reveal that the Co-N_<i>x</i> active sites along with the carbon defects can decrease the adsorption energy of intermediates (OH*, O*, and OOH*) and enhance the electron-transfer ability, thus boosting the OER process.