title: Lewis Basicity of Nitrogen-Doped Graphite Observed by CO2 Chemisorption.
abstract: The characteristics of CO2 adsorption sites on a nitrogen-doped graphite model system (N-HOPG) were investigated by X-ray photoelectron and absorption spectroscopy and infrared reflection absorption spectroscopy. Adsorbed CO2 was observed lying flat on N-HOPG, stabilized by a charge transfer from the substrate. This demonstrated that Lewis base sites were formed by the incorporation of nitrogen via low-energy nitrogen-ion sputtering. The possible roles of twofold coordinated pyridinic N and threefold coordinated valley N (graphitic N) sites in Lewis base site formation on N-HOPG are discussed. The presence of these nitrogen species focused on the appropriate interaction strength of CO2 indicates the potential to fine-tune the Lewis basicity of carbon-based catalysts.
authors.affiliation: Department of Applied Chemistry, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Kiuchi
authors.affiliation: Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Riku
authors.initials: R
authors.lastname: Shibuya
authors.affiliation: Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kondo
authors.affiliation: Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Nakamura
authors.affiliation: The Institute for Solid State Physics (ISSP), the University of Tokyo, Kashiwa, Chiba, Japan.|Synchrotron Radiation Research Organization, the University of Tokyo, Kashiwa, Chiba, Japan.|Present address: Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Hideharu
authors.initials: H
authors.lastname: Niwa
authors.affiliation: The Institute for Solid State Physics (ISSP), the University of Tokyo, Kashiwa, Chiba, Japan.|Synchrotron Radiation Research Organization, the University of Tokyo, Kashiwa, Chiba, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Miyawaki
authors.affiliation: Department of Applied Chemistry, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Kawai
authors.affiliation: Synchrotron Radiation Research Organization, the University of Tokyo, Kashiwa, Chiba, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Oshima
authors.affiliation: The Institute for Solid State Physics (ISSP), the University of Tokyo, Kashiwa, Chiba, Japan. harada@issp.u-tokyo.ac.jp.|Synchrotron Radiation Research Organization, the University of Tokyo, Kashiwa, Chiba, Japan. harada@issp.u-tokyo.ac.jp.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Harada
keywords: CO2 adsorption; Infrared reflection absorption spectroscopy; Lewis basicity; Nitrogen-doped carbon; X-ray absorption spectroscopy; X-ray photoelectron spectroscopy