Oxidative dehydrogenation of ethylbenzene over Zn1-xNixFe2O4 (x=0, 0.2, 0.5, 0.8 and 1.0) type systems: Effect of composition on surface properties and catalytic activities

The acid-base properties of a series of Zn-Ni ferrites, having the general formula Zn(1-x)NixFe(2)O(4), were measured and the catalytic activity as we ll as the selectivity of the oxidative dehydrogenation of ethylbenzene were examined. The activity and selectivity of this reaction were correlated we ll with the surface acid-base and redox properties of the catalyst. Basicit y of the systems was studied based on the adsorption studies using electron acceptors with different electron affinity values. The surface acidity of the system was evaluated using cyclohexanol decomposition studies. Both the limiting concentrations of electron accepters adsorbed and their cyclohexa nol dehydration activities have been correlated with catalyst composition t o understand the variation of strength distribution of acid-base centers wi th composition. Cation distribution in the spinel lattice influences their acido-basic properties, and hence, these factors have been considered as he lpful to evaluate the activity of the systems.