The nickel-support interaction as determining factor of the selectivity to ethylene in the oxidative dehydrogenation of ethane over nickel oxide/alumina catalysts

• Al 2 O 3 -Supported NiO improve the catalytic performance of bulk NiO in ethane ODH. • NiO-support interaction determine selectivity to ethylene. • NiO-support interaction determine the reducibility of catalysts. • High selectivity related also with a higher number of nickel and oxygen. vacancies. Nickel oxides supported on γ-alumina (Ni-loading from 5 to 30 wt% NiO) have been synthesized and tested in the oxidative dehydrogenation (ODH) of ethane in order to determine the importance of the NiO-support interaction. The best performance was achieved by the catalyst with 15 wt% NiO; higher NiO-loadings lead to the formation of unselective bulk-like NiO and lower Ni-loadings present high proportion of free alumina surface sites. The presence of oxalic acid and/or niobium in the synthesis gel resulted in the formation of NiO particles with similar size, but higher crystallinity and reducibility than the standard 15 wt% NiO catalyst. The obtained results have revealed that, in addition to NiO crystal size, the nickel oxide-support interaction determines the catalytic performance of these catalysts.