The present study investigates the catalytic n-butane dehydrogenation under oxygen free atmosphere using VOx supported on USY, NaY, gamma-Al2O3 and alpha-Al2O3. Experiments are developed at 520degreesC in a fixed bed microreactor. Catalyst characterization via TPR demonstrates the presence of different VOx species with the nature of these species being a function of the catalyst support. The acidic properties of the prepared catalysts are also evaluated using NH3 TPD with the following order of acidity being observed: VOx/gamma-Al2O3 > VOxM/alpha-Al2O3 > VOx/USY. Reactivity experiments show that the VOx/USY provides both the highest catalytic activity and butane selectivity, with the VOx/gamma-Al2O3 displaying a lower activity and butane selectivity and the other tested catalyst samples being essentially inactive. The superior performance of the VOx/USY catalyst is assigned to its mild acidity. (C) 2004 Elsevier B.V. All rights reserved.