2 and 10 oxygen o 2 at a temperature of 750 u00b0 c a pressure of 30 torr and a microwave power of 700 w the carbon nanotubes thus produced were sonicated in 70 sulfuric acid solution for 3 hours followed by filtration through a filter 2 production of carbon nanotubes having nanosized nickel on the surface thereof 0 1 g of the carbon nanotube samples obtained as described above were impregnated in 200 ml of each of acetone solutions containing 73 mm 21 mm 10 mm and 5 mm ni nitrate ni no 3 2 respectively and then stirred for 3 hours followed by drying at 60 u00b0 c the dried samples were reduced in a hydrogen atmosphere at 300 u00b0 c for 3 hours thus producing carbon nanotubes having nanosized nickel doped on the surface thereof the carbon nanotube having nanosized nickel doped on the surface thereof which have been produced as described above were first degassed at 350 u00b0 c in a vacuum 3 10 torr for more than 6 hours so as to completely remove gases from the carbon nanotubes next the carbon nanotubes were adsorbed with hydrogen at room temperature and 60 atm for 6 hours and then maintained at a temperature of u2212 190 u00b0 c with liquid nitrogen by a cryostat thus adsorbing hydrogen a hydrogen desorption test for the samples adsorbed with hydrogen as described above was performed by thermal desorption spectrum analysis tcd the samples were heated from u2212 190 u00b0 c to 500 u00b0 c at a rate of 4 5 u00b0 c min while hydrogen desorbed.