Dopamine-Carbonized Coating PtCo Catalyst with Enhanced Durability toward the Oxygen Reduction Reaction.

Stability is the main challenge for the application of PtCo catalysts because Co tends to leach during the electrochemical reaction. Herein, we immerse and adsorb dopamine to densely coat PtCo particles and subsequently thermally carbonize the coating into few-layer nitrogen-doped graphene to produce PtCo@NC. This coating effectively hinders direct contact between PtCo particles and the electrolyte, thereby enhancing the stability of the catalyst by preventing Ostwald ripening and suppressing competitive adsorption of toxic species, while also bolstering its antipoisoning ability. Experimental results indicate that the thin coating does not compromise the oxygen reduction reaction activity of the catalyst, showcasing a half-wave potential of 0.81 V in alkaline electrolytes. Spectroscopic results suggest that a strong bonding interaction between Pt and the pyridinic N of N-doped graphene contributes to the generation of a dense coating. The coating layer does not affect the four-electron reaction mechanism of the PtCo alloy, and the coordinatively unsaturated carbon atoms on PtCo@NC serve as active oxygen reduction reaction centers.