Oxidative dehydrogenation of n-butane on iron-zinc oxide catalysts

The oxidative dehydrogenation of n-butane to butenes over iron-zinc oxide catalysts was studied. X- ray diffraction (XRD), temperature-programmed reduction (TPR) and Mössbauer spectroscopy were used to try to identify the catalytically active phase. It was found that the presence of a zinc ferrite (ZnFe₂O₄) phase with a spinel structure yields high selectivity to butenes. The presence of a second phase, either α-Fe₂O₃ or ZnO, altered the product selectivity. α-Fe₂O₃ promoted the formation of carbon dioxide, while ZnO favored selectivity toward butadiene. Mössbauer spectroscopy indicated an electronic interaction between zinc oxide and the iron of the zinc ferrite. It is proposed that this electronic interaction may be responsible for the shift in selectivity to butadiene.