SPECIFIC FEATURES CONCERNING THE MECHANISM OF METHANE REFORMING BY CARBON-DIOXIDE OVER NI LA2O3 CATALYST/

The reforming of methane by carbon dioxide is studied over a Ni/La2O3 catalyst which presents an unusual catalytic stability compared to oth er nickel-based catalysts, A thorough TEM/EDX study combined with isot opic transient DRIFT and TAP experiments reveals the existence of a ti ght interface between a lanthanum carbonate phase and the nickel parti cles, A ''bi-functional'' mechanism is proposed to account for the obs erved kinetic behaviour: methane is activated on the Ni particles, car bon dioxide interacts with La2O3 to form carbonates which scavenge car bon from nickel at the Ni-La2O3 interface, thus restoring the Ni parti cles to their original state, This specific morphology of the active p hase is also assumed to hinder the formation of deactivating coke, whi ch explains the catalytic stability of such a catalyst. (C) 1997 Acade mic Press.