Hydrogen production via the direct cracking of methane over silica-supported nickel catalysts

We have investigated the catalytic cracking of methane as an alternative route for the production of hydrogen from natural gas. Nickel supported on silica was found to be active for this reaction producing stoichiometric amounts of hydrogen and carbon. SEM and TEM characterization of the spent catalyst indicated that carbon deposits on the catalyst in the form of hollow cylindrical filaments, with a nickel particle located on the tip of each filament. As a result, deactivation due to carbon deposition does not occur until the carbon filaments begin to interfere with each other and the silica surface, due to the spatial Limitations of the pore structure of the catalyst. The deactivated catalyst can be fully regenerated by either oxidation in air or steam gasification of the deposited carbon. Additional hydrogen is produced during the steam regeneration process. (C) 1998 Elsevier Science B.V.