Composition effect of metal species in (Ni, Fe, Co)-Bi-O/gamma-Al₂O₃ catalyst on oxidative dehydrogenation of n-butane to butadiene

The effect of metal oxide species in (Ni, Fe and/or Co) oxide-Bi₂O₃ over gamma-alumina support was investigated for n-butane oxidative dehydrogenation. Partial substitution of Ni up to 50% by Fe improved butadiene selectivity while same substitution with Co increased n-butane conversion. The ternary Ni-Fe-Co system (10 wt% Ni–5 wt% Fe–5 wt% Co–30 wt% Bi-O/gamma-Al₂O₃) showed the highest butadiene selectivity of 46.3% at n-butane conversion of 30%. The acid-base sites preferably adjusted by ternary main metal combination in hierarchical cohabitation of metal (Ni, Fe and Co) oxide, Bi₂O₃ and gamma-Al₂O₃ cooperate to accelerate butadiene selectivity at both 1st and 2nd step dehydrogenations due to an increased H₂ abstraction and 1-butene intermediate adsorption.