ORIGINAL PAPER Mechanism of CH 4 Dry Reforming on Nanocrystalline Doped Ceria-Zirconia with Supported Pt, Ru, Ni, and Ni–Ru A. S. Bobin • V. A. Sadykov • V. A. Rogov • N. V. Mezentseva • G. M. Alikina • E. M. Sadovskaya • T. S. Glazneva • N. N. Sazonova • M. Yu Smirnova • S. A. Veniaminov • C. Mirodatos • V. Galvita • G. B. Marin Ó Springer Science+Business Media New York 2013 Abstract Specificity of CH 4 dry reforming mechanism for Me-supported doped ceria-zirconia catalysts with high oxygen mobility was elucidated using a combination of transient kinetic methods (TAP, SSITKA) with pulse microcalorimetry and in situ FTIRS. Steady-state reaction of CH 4 dry reforming is described by a simple redox scheme with independent stages of CH 4 and CO 2 activa- tion. This is provided by easy CO 2 dissociation on reduced sites of oxide supports followed by a fast oxygen transfer along the surface/domain boundaries to metal sites where CH 4 molecules are transformed to CO and H 2 . The rate- limiting stage is irreversible transformation of CH 4 on metal sites, while CO 2 transformation proceeds much faster being reversible for steady-state surface. The oxygen forms responsible for CH 4 selective transformation into syngas correspond to strongly bound bridging oxygen species with heats of desorption &600–650 kJ/mol O 2 , most probably bound with pairs of Pr and/or Ce cations able to change their oxidation state. Ni ? Ru clusters could be involved in CO 2 activation via facilitating C–O bond breaking in the transition state, thus increasing the rate constant of the surface reoxidation by CO 2 . Strongly bound carbonates are spectators. Keywords Methane  Dry reforming  Me-supported doped ceria-zirconia  Oxygen bonding strength and reactivity  Mechanism  Transient kinetic studies 1 Introduction Catalysts comprising doped ceria-zirconia oxides with supported precious metals and/or Ni demonstrate a high activity and coking stability in carbon dioxide reforming of methane, which is explained by a high lattice oxygen mobility of these oxides and strong metal—support inter- action [1–12]. However, factors controlling main features of reaction mechanism on these catalysts, first of all, acti- vation of reagents, remain unspecified though they are known to be important for providing stable performance in CH 4 dry reforming [12–15]. Thus, Bradford and Vannice [14] proposed that CO 2 participates in the CH 4 DR reaction via the reverse water–gas shift (RWGS) reaction yielding OH groups, which then react with adsorbed CH x interme- diates to form formate-type species (CH x O). For Pt/Al 2 O 3 catalyst, O’Connor et al. [15] suggested that CH 4 activation proceeds on free Pt sites, and CO 2 activation is assumed to be the slowest step assisted by hydrogen to form adsorbed CO and OH. For Pt/ZrO 2 , participation in the reaction mechanism of hydroxocarbonates and formates stabilized on support was suggested [15]. On the other hand, Bychkov et al. [16, 17] demonstrated by using microcalorimetric measurements that for Pt/Al 2 O 3 CO 2 is activated via direct interaction with the surface carbon atoms, which is the A. S. Bobin  V. A. Sadykov (&)  V. A. Rogov  N. V. Mezentseva  G. M. Alikina  E. M. Sadovskaya  T. S. Glazneva  N. N. Sazonova  M. Y. Smirnova  S. A. Veniaminov Boreskov Institute of Catalysis SB RAS, Prospect Akademika Lavrentieva, 5, 630090 Novosibirsk, Russia e-mail: sadykov@catalysis.ru V. A. Sadykov  V. A. Rogov  N. V. Mezentseva Novosibirsk State University, Novosibirsk, Russia C. Mirodatos Institut de Recherches sur la Catalyse et l’Environnement de Lyon, Lyon, France V. Galvita  G. B. Marin University of Gent, Ghent, Belgium 123 Top Catal DOI 10.1007/s11244-013-0060-z