N-doped carbon-stabilized PtCo nanoparticles derived from Pt@ZIF-67: Highly active and durable catalysts for oxygen reduction reaction

The development of catalysts with high activity and durability for the cathodic oxygen reduction reaction (ORR) in both alkaline and acidic media is important for improving the performance of the proton exchange membrane (PEM) fuel cells. This can be achieved by dispersing Pt-based alloy nanoparticles inside N-doped porous carbon frameworks. However, it still requires the development of a facile method towards synthesizing this unique hybrid structure. In this work, we demonstrate that N-doped carbon-stabilized PtCo nanoparticles (PtCo@NC) can be facilely synthesized via thermal decomposition of Pt-incorporated Co-based zeolitic imidazolate framework (Pt@ZIF-67). The thickness of the carbon framework can be optimized to enable excellent durability, in sharp contrast to a commercial Pt/C catalyst. The mass activities achieved by optimizing the thickness of the carbon framework are 0.80 and 0.82 A·mgPt –1 at 0.9 V vs. RHE in alkaline and acidic electrolytes, respectively, which are nearly 8 times greater than those of the Pt/C. This work provides an alternative approach to low-cost and high-performance catalysts for both alkaline and acidic fuel cells.