Graphitic Carbon-Based Core-Shell Platinum Electrocatalysts Processed Using Nickel Nanoparticle Template for Oxygen Reduction Reaction

Abstract Extensive efforts have aimed at securing stable Pt-based electrocatalysts having both the performance-efficiency and long-term durability particularly for proton-exchange membrane fuel cells. Herein, we introduce an unprecedented electrocatalyst architecture based on a core-shell phase-mediated Pt/carbon black (CB) support structure which was enabled by the graphitization process using a Ni nanoparticle template. A ~1.03 nm-thick shell layer of graphitic carbon (GC) formed around the surface of ~9 nm-scale Ni core-nanoparticles via the dissolution-precipitation process with the annealing step of Ni on CB. The final Pt/GC/Ni/CB catalyst demonstrated noticeably better electrocatalytic performance in oxygen reduction reaction than that of the catalyst without the GC layer. The accelerated durability test with 5,000 cycles confirmed the advantages of the GC shell layer by demonstrating less electrochemical degradations by ~4.4 times in electrochemical surface area and ~2.5 times in the half-wave potential, compared to those of the reference sample.