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 cathodicoxygen reduction reaction （ORR） in both alkaline and acidic media is importantfor improving the performance of the proton exchange membrane （PEM） fuelcells. This can be achieved by dispersing Pt-based alloy nanoparticles insideN-doped porous carbon frameworks. However, it still requires the developmentof 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-incorporatedCo-based zeolitic imidazolate framework （Pt@ZIF-67）. The thickness of the carbonframework can be optimized to enable excellent durability, in sharp contrastto a commercial Pt/C catalyst. The mass activities achieved by optimizing thethickness of the carbon framework are 0.80 and 0.82 A-mg^-1, at 0.9 V vs. RHE inalkaline and acidic electrolytes, respectively, which are nearly 8 times greaterthan those of the Pt/C. This work provides an alternative approach to low-costand high-verformance catalvsts for both alkaline and acidic fuel cells.