CO2 reforming of methane over supported LaNiO3 perovskite-type oxides

This work investigated the performance of supported LaNiO3 perovskite-type oxides for the CO2 reforming of methane. The methane and CO2 conversion increased at the beginning of reaction for LaNiO3 and LaNiO3/Al2O3 catalysts. On the other hand, conversion remained quite constant for LaNiO3/CeSiO2. in situ XPS experiments under reaction conditions revealed that the metallic Ni particles were oxidized by CO2 from the feed for LaNiO3 and LaNiO3/Al2O3 catalysts. Ceria support was preferentially oxidized, limiting the oxidation of the metallic phase. Raman spectroscopy and thermogravimetric analysis showed that carbon was formed mainly over LaNiO3 and LaNiO3/Al2O3 catalysts. Supporting LaNiO3 over CeSiO2 almost completely suppressed carbon deposition. in situ XPS experiments showed a continuous change of ceria oxidation states between Ce4+ and Ce3+ under reaction conditions. This result in a high oxygen mobility of ceria support that reacts with carbon, inhibiting the formation of nickel carbide and consequently the nucleation and growth of carbon filaments.