title: Effects of gas adsorption on the electrical conductivity of single-wall carbon nanohorns.
abstract: We present significant electrical conductivity responses of the pelletized as-prepared and oxidized (ox-) single-wall carbon nanohorns (SWNHs) on adsorption of CO(2) and O(2). The morphological and pore structures of both pelletized SWNHs were examined by transmission electron microscopy (TEM) and nitrogen adsorption isotherm, leading to explicit evidences of the formation of nanoscale windows on the wall by oxidation. The SWNH and ox-SWNH induced a semiconducting behavior, strongly responded to CO(2) and O(2) adsorptions, and each exhibited n-type- and p-type-like conductivities. The electrical conductivity increase and decrease for CO(2) and O(2) adsorption, respectively, were observed for SWNH, whereas ox-SWNH showed a marked electrical conductivity drop on CO(2) adsorption and almost no change on O(2) adsorption. The dramatically different electrical conductivity response of ox-SWNH is presumed to be ascribed to the annihilation of pentagons in the single graphene wall by oxidation.
authors.affiliation: Graduate School of Science and Technology, Chiba University, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Urita
authors.forename: Shinya
authors.initials: S
authors.lastname: Seki
authors.forename: Shigenori
authors.initials: S
authors.lastname: Utsumi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Noguchi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kanoh
authors.forename: Hideki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Hattori
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ochiai
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Aoki
authors.forename: Masako
authors.initials: M
authors.lastname: Yudasaka
authors.forename: Sumio
authors.initials: S
authors.lastname: Iijima
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000327:Adsorption; D002245:Carbon Dioxide / Q000737:chemistry*; D004553:Electric Conductivity; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*
chemical_list: D037742:Nanotubes, Carbon; D002245:Carbon Dioxide; D010100:Oxygen