CO2 and CO hydrogenation over Ni-supported materials

This work reports on the fundamental properties of nanostructured catalysts active in the main carbon oxides' conversion processes for sustainable energy supply: methanation and co-methanation of CO2. Transition metals (e.g. Ni, Pd, Pt, Co, Ru, Rh) are active species in both reactions. Ni has been the most studied because of its cheapness. Monometallic and bi-metallic Ni and Ni3Fe catalysts supported on Gadolinia-doped ceria (GDC) have been synthesized, characterized and tested in the temperature range 200600 degrees C. In the methanation reaction, the monometallic catalyst showed higher performance with respect to the bi-metallic catalyst. At 400 degrees C, the CO2 conversion overcomes 90% with CH4 selectivity of 100%. In co-methanation, the highest CO2, CO and H-2 conversion values over monometallic Ni/GDC catalyst were obtained at 300 degrees C; at higher temperatures, conversion decreases. The GDC support plays a pivotal role in both reactions, enhancing the basicity of the catalyst and improving the dissociation of carbon oxide species adsorbed on Ni sites.