Molecular potential structures of heat-treated single-wall carbon nanohorn assemblies

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 intraparticle pore and the interparticle space is close to 1000 K. Although the SWNH without the heat-treatment has no open intra-nanohom space, the intraparticle pores open with the high-temperature treatment in O-2. The heat-treatment at 693 K opens almost perfectly the intraparticle pores, leading to 0.47 mL g(-1) of the micropore volume and 1010 m(2) g(-1) of the specific surface area. The subtraction 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.