Hollow Porous Carbon-Confined Atomically Ordered PtCo3 Intermetallics for an Efficient Oxygen Reduction Reaction

PtM3 alloys have demonstrated superior oxygen reduction reaction (ORR) activity due to the strong strain effect caused by non-noble metal cores. However, the serious corrosion of non-noble metals in acid solutions is still challenging. Herein, a hollow porous N-doped carbon sphere-encapsulated PtCo3 intermetallic electrocatalyst (O-PtCo3@pHNCS) is successfully prepared through Co pre-embedding and the subsequent impregnation-reduction method. The Co pre-embedding step is responsible for the formation of abundant mesopores, and the subsequent impregnation-reduction process leads to Pt-Co ordering and carbon encapsulation. Benefiting from the accelerated mass transfer process, enhanced metal interaction, and physical confinement effect, O-PtCo3@HNCS exhibits excellent ORR activity and durability with negligible half-wave loss after long-term stability test in acid solutions. The ordered PtCo3 nanoparticles tightly anchored in the carbon matrix without obvious aggregation, sintering, and agglomeration, responsible for the superior durability. The strategy for the carbon confinement in this work paves the way for achieving highly efficient catalysts with low Pt content, which can be used in various energy-related systems.