Performance of Ni/La_2O_3 catalyst in carbon bioxide reforming of methane to synthesis gas

摘要

The rate of carbon dioxide reforming of methane over a Ni/La_2O_3 catalyst is found to increase during the initial 2-5h and then tends to be invariable with time on stream. A kinetic isotopic study shows that the reaction rate is reduced, by a factor of 1.2-2.0, upon switching the reactant mixture from CH_4/CO_2 to CD_4/CO_2, suggesting that methane activation is a slow step. Chemisorptive studies indicate that a portion of the Ni surface is decorated with lanthanum species originating from the La_2O_3 support, thus suppressing CO chemisorption and disproportionation. Mechanistic studies by FTIR, XRD, XPS and SIMS suggest that the interaction between nickel and lanthanum species creates a new type of synergetic sites at the Ni-La_2O_3 interfacial area, which offer active and stable performance of carbon dioxide reforming of methane to synthesis gas over the stated catalyst.