Catalysis Today 61 (2000) 43–48 Selective oxidehydrogenation of ethane with CO 2 over CeO 2 -based catalysts Rita X. Valenzuela a , Gema Bueno a , Vicente Cortés Corberán a,∗ , Yide Xu b , Changlin Chen b a Instituto de Catálisis y Petroleoqu´ ımica, CSIC, Campus UAM-Cantoblanco, 28049 Madrid, Spain b State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, PO Box 110, Dalian 116023, PR China Abstract Ceria catalysts were found active and selective to the oxidehydrogenation of ethane (ODE) with CO 2 and the actual contribution for C 2 H 4 formation from heterogeneous catalysis was 75–55% in the range 953–993 K. The presence of calcium ions in solid solution in the ceria crystalline network increased significatively the selectivity to ethene and the efficiency of CO 2 as oxidant in the heterogeneous reaction. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Ceria catalysts; Oxidehydrogenation of ethane; CO 2 as oxidant 1. Introduction To reach higher selectivities to desired products is a main challenge in development of the catalytic pro- cess of oxidative dehydrogenation of light alkanes. This is because various oxygen species are in dynamic equilibrium together with oxygen in gas phase and different oxidation reactions are taking place simulta- neously. In order to avoid such complicated reaction patterns, there are several reports which propose using inert CO 2 as an oxidant for the selective conversion of alkanes C 1 –C 3 in olefins and syngas [1–6]. CO 2 can dissociate on the catalyst surface to produce active oxygen species as expressed in Eq. (1) CO 2 ⇒ CO + O (1) Krylov et al. [3] showed that manganese oxide catalysts were active for these reactions. The prop- ∗ Corresponding author. Fax: +34-9158-547-60. E-mail address: vcortes@icp.csic.es (V. Cort´ es Corber´ an). erties of these catalysts can be modified by addition of other oxides (Cr, Ca, K) and their use was studied in the transformation of different organic compounds (olefins, alcohols) [1]. Other catalytic systems like PbO–MgO [2] or La 2 O 3 –ZnO [5] have been studied in OCM with CO 2 , producing high selectivities to C 2 products. Nevertheless, the mechanisms of reaction of organic compounds with CO 2 are not clear. However, it is noteworthy that most data presented in literature were obtained under high temperature (around 1000 K), and certainly, under such a reaction temperature, dehydrogenation of light alkane in gas phase is seriously involved. For example, the ther- modynamic equilibrium of ethane dehydrogenation at 1023 K is about 80%, whereas the equilibrium of the reaction C 2 H 6 + CO 2 ⇒ C 2 H 4 + CO + H 2 O (2) is about 57% at the same temperature. Therefore, it is necessary and of significance to identify the real contribution from heterogeneous catalysis. 0920-5861/00/$ – see front matter © 2000 Elsevier Science B.V. All rights reserved. PII:S0920-5861(00)00366-7