Hydrogen Storage in Carbon Nanotubes: Residual Metal Content and Pretreatment Temperature

Hydrogen storage in MWNT was enhanced ®ia the catalytic acti®ity of NiMgO. The magnitude of the hydrogen to metal ratio for the MWNTrNiMgO system, combined with temperature programmed adsorption and desorption studies, showed hydrogen spillo®er from the catalyst to the carbon surface. Metal doping combined with temperature acti®ation studies showed that both nickel and magnesium are acti®e in the catalytic process. The yield, quality, and carbon-metal contact were shown to affect hydrogen uptake. Higher pretreatment temperatures enhanced uptake, for both lowand high-pressure measurements, due to increased carbon-metal contact and acti®ation of ( ) the catalyst. At 69 bar or 1,000 psia , the hydrogen adsorption and desorption of the MWNTrNiMgO system were 3.7% and 3.6%, respecti®ely.