Adsorption properties of N-2, H-2 on SWNTs was studied by varying the KOH-modification temperature. The structure change of SWNTs through KOH-modification was investigated by using N-2 adsorption at 77 K. Hydrogen adsorption of the as-received SWNT and SWNT-x was performed using a volumetric apparatus at 77 K. The total surface area and micropore volume increased, while the average pore width, w, decreased, as the KOH-modification temperature decreased. The micropore structure in SWNTs was destroyed at high KOH-modification temperature. The amount of N-2, H-2 adsorbed depended strongly on the temperature of modification and was inversely proportional to that temperature. (c) 2006 Elsevier B.V. All rights reserved.