Phosphorus Incorporation Increases the Oxygen Electrocatalytic Activity of Co–N Catalysts

Abstract

Transition metal and nitrogen codoped graphitic carbon materials with Co–N bonds serve as key non-noble-metal catalysts for the oxygen evolution reaction (OER). To enhance catalytic efficiency, we explore the anchoring of Co–N bonds on nitrogen-doped graphitic carbon (NC) substrates with varied phosphorus content. The catalyst is synthesized through a straightforward sintering and phosphating process of ZIF@DCA in a tube furnace. X-ray photoelectron spectroscopy (XPS) demonstrated that the Co–N bonds effectively formed an efficient charge transfer channel, removing the barrier that separated the Co–N active site from the work electrode surface. Phosphorus is uniformly distributed across the Co–N substrate, ensuring the exposure of most Co–N active sites during the electrochemical reaction. With favorable structural and electronic attributes, P/Co–N-2 showcases the lowest overpotentials at 10 and 300 mA cm^–2, which are 200 and 300 mV, respectively. Additionally, it demonstrates stable performance over 100 h in 1 M KOH, outperforming other similar materials and RuO₂. This study offers critical insights for the rational design of Co–N structures, exploring the interplay between structure, composition, and activity in electrochemical reactions.