The effect of Ce and H2S on selective hydrogenation of diolefins using NiPdCe(x)/Si-Al-coated structured packing catalyst was studied for the selective hydrogenation of butadiene in the presence of benzene. The structured packing was coated by a silico-aluminate in which Ce, Ni and Pd were incorporated during successive impregnations. The catalyst was activated in the presence of hydrogen containing 10 ppm of hydrogen sulfide and tested in a continuous stirred tank reactor (CSTR) under different operating conditions. The catalysts were characterized by XRD, Al-27- and Si-29-NMR, TPR(H-2), IR, XPS, physical and chemical analysis. The results indicated that Ce and hydrogen sulfide affect the metal dispersion, the electronic configurations of the metals on surface and the acidity of the catalyst. Therefore the activity and selectivity is modified by both Ce and H2S at constant Ni and Pd contents. The results were interpreted using a previously developed kinetics model. (C) 2012 Elsevier B.V. All rights reserved.