Development of La doped Ni/CeO2 for CH4/CO2 reforming

Methane dry reforming (MDR) allows the transformation of carbon dioxide and methane, the two main greenhouse gases, into syngas. Given the high endothermicity of the process, it is necessary to produce a catalytic system that is very active, selective and resistant to coking deactivation; this work focuses on the development of a heterogeneous catalyst based on nickel supported on cerium oxide. Several strategies of synthesis of the catalysts were studied with particular attention to the lanthanum addition methodology. Both supports and catalysts, fresh and used, were deeply characterized by different techniques (N₂ physisorption, TPR, XRD, SEM). The effect of temperature on activity and selectivity of the different catalysts was also studied. A positive effect of lanthanum addition is strongly related to the synthetic methodology. Incipient wetness impregnation of lanthanum precursor on an already calcined ceria has led to the best catalytic activity. This behaviour is due to a more effective interaction between nickel and the support, which results in a higher dispersion of the active phase. The structural modifications have led to an improvement of the redox pump of the ceria, reducing the formation of coke during the reaction and improving the stability on time on stream.