Scrutinizing different catalytic processes in the (Gd–La) codoped CeO2–NiO-carbonate membrane reactor, implying CO2 permeation mechanisms

In recent years, new and novel ceramic carbonate membrane reactors have received attention due to their high capabilities. Within this context, a membrane reactor system implies a gas permeation combined with a catalytic reaction process, resulting in a synergetic effect of a bifunctional material, which intensifies the whole process. This work presents the use of a (Gd–La) codoped CeO2–NiO-carbonate membrane reactor, for two different processes; i) carbon monoxide (CO) oxidation and ii) dry methane (CH4) reforming, in which carbon dioxide (CO2) permeation is needed. The (Gd–La) codoped CeO2–NiO powder was obtained by the so called one-pot method, obtaining a Gd–La codoped ceria and nickel oxide mixture, determined by X-ray diffraction and high resolution transmission electron microscopy. In any case, the formation of these phases probed to possess a better CO2 permeation than that obtained when a mechanical mixture of Ce0.85Gd0.15O2-δ and LaNiO3 was evaluated. This membrane reactor showed efficient CO oxidation and CO2 permeation yields, which were highly improved through the oxygen (O2) addition in the feed and/or sweep membrane sides. In the dry CH4 reforming reaction, this composition was able to perform the reaction, although it was importantly improved by a catalyst addition (LaNiO3) being the CO2 permeation the limiting step of the whole reaction process.