Pt Nanoparticles Anchored on N-Doped Carbon Containing Single Co Atoms as Catalyst for the Oxygen Reduction Reaction

The roadblock for commercialization of proton exchange membrane fuel cells originates from high-cost and insufficient oxygen reduction reaction (ORR) activity and durability of Pt-based catalysts. Herein, a Co-N-doped porous carbon (Co-NPC) is proposed to stabilize the Pt nanoparticle by means of interactions between Pt species and atomic Co-N_x moieties, resulting in 8.38 wt % Pt loading and an ultrasmall size of 2.2 nm in the resulting Pt/Co-NPC catalyst. Thanks to modulation of atomic Co-N_x moieties to ultrasmall Pt nanoparticles, the Pt/Co-NPC catalyst shows outstanding ORR activity in acidic media, including a half-wave potential (E_1/2) of 0.90 V and a mass activity (MA) of 0.701 A mg_Pt^–1 at 0.9 V, far superior to the commercial Pt/C catalyst (E_1/2 = 0.87 V, MA = 0.143 A mg_Pt^–1). More importantly, excellent ORR durability of Pt/Co-NPC, revealed by its unchanged activity after 15,000 potential cycling tests, is demonstrated due to the strong coupling interactions between Pt and atomic Co-N_x moieties to stabilize the Pt nanoparticles. This work provides a valuable strategy to develop high-activity and stable low-Pt catalysts that are likely to spark widespread interest in fuel cells.