ZrxMg1-xO supported cobalt catalysts for methane decomposition into COx-free hydrogen and carbon nanotubes

ABSTRACTZirconia-magnesia supported cobalt catalysts with various Zr/Mg atomic ratios were prepared and evaluated for non-oxidative catalytic decomposition of methane to produce COx-free hydrogen and carbon nanotube. The catalytic performance of the catalysts was performed in a continuous fixed bed flow reactor at 700°C under atmospheric pressure. The fresh and spent catalysts were characterized by XRD, TPR, BET, TEM, and Raman spectroscopy. The results showed that the change in Zr/Mg ratio of the mixed oxide support has a significant effect on the catalytic performance of the active Co metal. The catalyst 30%Co/Zr0.8Mg0.2 showed the highest activity and stability within the used series of catalysts with hydrogen yield reached up to 79%. Both Co/Mg1.0 and Co/Zr1.0 showed poor stability due to strong Co-Mg interaction and aggregation of Co species on Zr support, respectively. All catalysts produced mainly MWCNTs with different diameters depending on the Zr/Mg ratio. The outer diameter increased with increa...