title: Single-walled carbon nanotube network with bimodal pore structures of uniform microporosity and mesoporosity.
abstract: We characterized single-walled carbon nanotubes before and after HNO3/H2SO4 treatments for different times by scanning electron microscopy, Raman spectroscopy, and N2 adsorption at 77 K. Single-walled carbon nanotube assembly revealed a bimodal pore structure of microporosity (surface area of 476 m2 g(-1)) and mesoporosity (surface area of 476 m2 g(-1)) with a high total surface area of 1048 m2g(-1). The microporosity increased prominently after HNO3/H2SO4 treatments, whereas the mesoporosity decreased progressively with the treatment time. The HNO3/H2SO4 treatment of nanotubes induced an aggregation and alignment that should transform larger mesopores of nanotube assemblies into smaller ones, and smaller mesopores into micropores, resulting in the decrease of external surface area. This effect was attributed to the presence of abundant defects on the tube wall that were saturated by functional groups during the acid treatment of the single-walled carbon nanotubes.
authors.affiliation: BK21 Physics Division, Institute of Basic Science, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Cheol-Min
authors.initials: CM
authors.lastname: Yang
authors.forename: Dong Young
authors.initials: DY
authors.lastname: Kim
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee
mesh_terms: D000327:Adsorption; D003460:Crystallization / Q000379:methods*; D008422:Materials Testing; D008968:Molecular Conformation; D037742:Nanotubes, Carbon / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D017942:Nitric Acid / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D037742:Nanotubes, Carbon; D013464:Sulfuric Acids; D017942:Nitric Acid; D009584:Nitrogen; C033158:sulfuric acid