Core@Shell Pt₃Co@Pt/C Nanoparticles as an Electrocatalyst for the Oxygen Reduction Reaction

Introducing transition metals to form platinum-based alloys is an effective strategy for optimizing oxygen reduction reaction (ORR) performance, while the disordered nanostructure of the alloy catalyst has limited improvement in the ORR durability. Especially, there are practical challenges in controlling and maintaining the ordered nanostructure of platinum-based alloys during the ORR. In this study, a highly ordered core–shell structural Pt 3 Co@Pt/C catalyst was synthesized via a facile impregnation-annealing and acid-washing procedure with finely controlling the Pt/Co atom ratio, annealing temperature, and time. The obtained Pt 3 Co@Pt/C catalyst exhibited a core–shell nanostructure as well as enhanced ORR activity when compared to commercial Pt/C, with a mass activity (MA) of A mg Pt –1 and a specific activity (SA) of 0.72 mA cm –2, marking improvements by factors of 2.05 and 2.67, respectively. The superior catalytic performance is attributed to the optimized electronic structure of Pt induced by Co doping, which was revealed by further physicochemical characterization analysis. Following 30,000 cycles of accelerated degradation testing (ADT), Pt 3 Co@Pt/C retained 73.58% of its initial electrochemical surface area (ECSA), 40% of MA, and 55.56% of SA, with both MA and SA remaining 2 to 4 times higher than commercial Pt/C. Notably, the catalyst displayed minimal performance deterioration between 10,000 and 30,000 ADT cycles and nearly negligible catalyst nanoparticle aggregation, attributable to the efficacious shielding provided by the acid-washed core–shell nanostructure. This work developed highly durable core–shell Pt 3 Co@Pt/C nanoparticles for the ORR, as well as provided a universal reference strategy for controlling the ordered structure of platinum-based alloys doped with other transition metals.