| AVS 62nd International Symposium & Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS+AS+EN-TuM |
| Session: | Mechanistic Insight of Surface Reactions: Catalysis, ALD, etc. - I |
| Presenter: | Takahiro Kondo, University of Tsukuba, Japan |
| Authors: | T. Kondo, University of Tsukuba, Japan D. Guo, University of Tsukuba, Japan R. Shibuya, University of Tsukuba, Japan C. Akiba, University of Tsukuba, Japan S. Saji, University of Tsukuba, Japan J. Nakamura, University of Tsukuba, Japan |
| Correspondent: | Click to Email |
Nitrogen-doped carbon materials have been found to demonstrate high electrocatalytic activity for oxygen reduction reaction (ORR) as the non-metal catalysts but the active site is still under debate. This is due to the complexity of the real catalysts, such as mixing of different type of N and inhomogeneity in both structure and conductance. Here we designed the nitrogen doped graphite (HOPG) model catalysts with different type of N dominance and its concentration to directly clarify the ORR active site. ORR measurements showed that active site was created by pyridinic N (N bonded to two carbon atoms). The ORR active site was ascribed to the carbon atom with Lewis base property created by neighbour pyridinic N based on the investigations of intermediate state of ORR, localized electronic states at carbon next to pyridinic N and CO2 adsorption property by X-ray photoelectron spectroscopy (XPS), scanning tunneling spectroscopy (STS) and temperature programmed desorption (TPD), respectively. The ORR activity of model catalyst per pyridinic N concentration was then found to be in good agreement with that for real nitrogen-doped graphene catalyst.