Molecular Potential Structures of Heat-Treated Single-Wall Carbon Nanohorn Assemblies

摘要

The microporosity of the heat-treated single-wall carbon nanohorn (SWNH) particles is characterized by nitrogen adsorption at 77 K and the molecular potential calculation using the function, which is based on the Lennard-Jones pair potential. The depth difference of the molecular potential for N_2 between the SWNH intrapartaicle pore and the interparticle space is clost to 1000 K. Although the SWNH without the heat-treatment has no open intra-nanohron space, the intraparticle pores open with the high-temperature treatment in O_2. The heat-treatment at 693 K opens almost perfectly the intrapartiacle pores, leading to 0.47 mL g~(-1) of the micropore volume and 1010 m~2 g~(-1) of the specific surface area. The substraction of the N_2 adsorption isotherm of the SWNH from that of the SWNH treated at 693 K gave the N_2 adsorption isotherm only in the intraparticle pore spaces. The adsorption sites derived from the difference adsorption isotherm are assigned to the pores having different interaction potentials.