Study of Cyclic Ni3Al Catalyst Pretreatment Process for Uniform Carbon Nanotubes Formation and Improved Hydrogen Yield in Methanol Decomposition

The 50 μm thick Ni3Al thin foils were investigated as the solid-state catalyst. In this study, a cyclic Ni3Al catalysts pretreatment process was performed to obtain more uniform carbon nanotubes and gradual fragmentation of Ni nanoparticles. In temperature about 500oC the cyclic methanol decomposition was conducted. The change of hydrogen yield in methanol decomposition over tested catalysts in following cyclic pretreatment was analyzed in details. The carbon nanostructures formed during methanol decomposition was investigated by SEM, BET, XRD and Raman spectroscopy. It has been proven that the Ni nanoparticles agglomerated with following consecutive cycles, caused gradual decrease of methanol conversion and hydrogen yield in every next cycle.