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

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.