Study of LaNi1-xCoxO3 Perovskites-Type Oxides Either Pure or Mixed with SiO2 as Catalytic Precursors Applied in CH4 Dry-Reforming

The aim of this study was to synthesize LaNi1-xCoxO3 (x = 0.0, 0.1, 0.2, 0.5 and 1.0) perovskite-type oxides and investigate the materials as catalytic precursors, either pure or mixed with silica, in dry reforming of methane (DRM). All catalytic precursors were characterized by X-ray Powder Diffraction (XRPD), X-ray fluorescence (XRF), temperature-programmed reduction with hydrogen (H-2-TPR), temperature-programmed surface reaction (TPSR) under CH4/CO2 mixtures. After reduction in hydrogen these catalysts were tested at 1023 K in DRM during 24 h. Substitution of Ni by Co resulted in a decrease in catalytic performances, demonstrating the primary role of Ni in the catalytic activity of these materials. LaNiO3 sample showed high stability during 24 h time on stream. CO2 conversion was always higher than that of CH4. All samples presented a H-2/CO ratio lower than 1, an indication of side reactions occurrence, such as RWGS. Post activity test characterizations revealed the presence of carbon-based deposits mainly with graphitic structure, and the formation of La-oxycarbonates. A mechanical mixture of the perovskites with non-porous silica led to an increase of both CH4 and CO2 conversions as well as of H-2/CO ratio. [GRAPHICS] .