A comparative study of nickel molybdate and carbon nanotube supported nickel molybdate catalysts for the oxidative dehydrogenation of n-octane.
A comparative study of the activation of n-octane over nickel molybdate (α and β-phases), carbon nanotubes and carbon nanotube supported nickel molybdate was carried out in the gas phase in a plug flow fixed bed reactor having air as the oxidant. All four catalysts were found to be catalytically active in the oxidative dehydrogenation reaction. It was found that the higher temperature β-phase molybdate is catalytically more active and selective than the α-phase for the production of valuable oxygenates and C8 olefins at isoconversion and under isothermal conditions. Carbon nanotubes were found to be catalytically active with a higher selectivity to oxygenates and C8 olefins and a lower selectivity to COx as compared to α-NiMoO4. Carbon nanotube supported α-nickel molybdate showed a decrease in selectivity to CO2 as compared to the α-NiMoO4 catalysts alone and yielded the highest selectivity to the total C8 olefins.