Role of lattice oxygen during CO2 reforming of methane over NiO/MgO solid solutions

Abstract

The CO2 reforming of methane over reduced NiO/MgO solid solution catalysts was studied at 800°C by a novel transient method, which couples a broadened pulse of CH4/CO2 with a step change to the carrier gas and/or with a sharp isotopic pulse of either 18O4, CO182 or 13CO162. The response curves indicated that two kinds of oxygen were formed over the catalysts during reaction: adsorbed oxygen which reacts fast with C species and lattice oxygen which reacts more slowly with C species. One concludes that a redox cycle of lattice oxygen formation through the oxidation of Ni and its reaction with C species takes place on the catalyst surface.