MOF-Derived Nitrogen-Doped Carbon-Supported Ordered Intermetallic PtNiCo Nanoparticles for the Oxygen Reduction Reaction

Abstract Metal−organic frameworks (MOFs) have gained attention as promising catalyst supports due to their tunable structures, high surface areas, and excellent thermal stability. In this work, ZIF-67, a cobalt-based MOF, is employed as a precursor to synthesize a nitrogen-doped carbon (NC) support for ordered intermetallic PtNiCo nanoparticles, forming a PtNiCoN-NC electrocatalyst with significantly enhanced oxygen reduction reaction (ORR) activity and durability compared with carbon-supported PtNi and commercial Pt/C catalysts. Specifically, the PtNiCoN-NC electrocatalyst achieved a mass activity of 0.97 A mgPt−1 at 0.90 V, a half-wave potential (E1/2) of 0.96 V, and excellent stability after 30,000 accelerated durability cycles in 0.1 M HClO4. The enhanced ORR activity and durability are associated with combined effects of the ordered intermetallic core−shell structure, nitrogen incorporation, and strong metal−support interactions provided by the ZIF-67-derived porous carbon support. In situ X-ray absorption spectroscopy further revealed suppressed Pt-oxidation and preserved Pt−Ni coordination under electrochemical operating conditions, demonstrating the structural stability of the intermetallic catalyst during the ORR. These findings contribute to the development of design principles for highly active and durable Pt-based ORR electrocatalysts.