In this work,the Co-ZSM-5 catalysts are prepared by solid exchange and by impregnation method with variable cobalt amounts.The effect of the catalyst washing in order to remove the residual cobalt is studied.Nitrogen physisorption,XRD and TPR are the main techniques used to characterize these catalysts.The obtained results show that bulk oxides,cobalt oxide clusters and cobalt ions could be present on the prepared Co-ZSM-5 catalysts.The impregnation methods is more effective for Co dispersion than the solid exchange procedure.The catalytic activity of the Co-ZSM-5 catalysts in ethane ammoxidation shows that the cobalt oxide cluster sites are more active than the cobalt ion sites.However,an optimal concentration of these cobalt species is essential for ethane ammoxidation.
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