CO2 reforming of CH4 over Co–La-based perovskite-type catalyst precursors

A series of perovskite-type oxides based on La–Sr–Co (La1−xSrxCoO3) were synthesized by the auto combustion method and used as precursors for the catalytic methane dry reforming (MDR) at 1073 K, atmospheric pressure under continuous flow of reactant gases with a CH4:CO2 = 1:1 ratio. Catalysts were characterized by techniques such as X-ray diffraction (XRD), BET specific surface area, temperature-programmed reduction-oxidation (TPR–TPO) and scanning-transmission electron microscopy (SEM–TEM). Formation of La–Sr–Co–O solid solutions was confirmed by the more intense diffraction peaks and cell parameter measurements. It was observed that the activation/reduction process occurs through intermediary species producing Co0 nano-size particles over the SrO and La2O3 phases, which are highly dispersed in the La2O2CO3–SrO solid matrix responsible for the high activity and low carbon formation despite the severe reaction conditions used. The presence of Sr in doping quantities slightly promotes secondary reactions such as carbon formation and water–gas shift retarding partially the dry reforming reaction.

► The precursors solids La1−xSrxCoO3 were synthesized by the auto combustion method.
► XRD in situ confirmed the thermal stability and transformations of the perovskite.
► Co0 nanoparticles highly dispersed in La2O2CO3–SrO are obtained by reduction process.
► The interaction between CO2 and La2O3 produces La2O2CO3 phase.
► The catalysts inhibit carbon formation despite the severe reaction conditions.