Presentation Information
[3H12]Fabrication of nitrogen-doped HOPG model catalysts for understanding the role of local structures in electrode catalysis
*Rafiq Arsyad1,2, Bang Lu1,2, Satoru Takakusagi1,2, Kotaro Takeyasu1,2 (1. Graduate School of Environmental Science, Hokkaido University. , 2. Institute for Catalysis, Hokkaido University)
To advance the understanding of carbon-based catalyst mechanisms, we developed a controllable model system linking nitrogen bonding configurations to oxygen reduction reaction (ORR) activity in acidic media. This platform enables identification of the roles of pyridinic, graphitic, pyrrolic, and five-membered ring nitrogen, which is critical for designing high-performance, metal-free ORR catalysts. Building on our previous work clarifying the role of pyridinic nitrogen with a molecular model system [1,2], we employed Highly Oriented Pyrolytic Graphite (HOPG) with plasma-assisted nitrogen doping to probe additional configurations. This method precisely controls nitrogen content and bonding without altering morphology. ORR tests in O2-saturated 0.1 M HClO4 showed the highest onset potential (0.327 V vs RHE at –0.001 mA/cm2) at 30% plasma power, where pyrrolic nitrogen dominated, while higher powers reduced activity due to surface damage or less active species.