CO methanation in CO$_2$-rich reformate on supported Ru catalysts: Interplay between activation/reaction conditions, Ru particle size and selectivity

Supported Ru catalysts show a very high selectivity for the selective methanation of CO in CO2-rich H2 feeds. Based on a combination of kinetic measurements, in situ DRIFTS and in situ EXAFS measurements on Ru/zeolite and Ru/Al2O3 catalysts, the dependence of the selectivity on the Ru particle size will be shown, and how both of them depend on the nature of the support, the activation procedure and the reaction conditions, especially the water content in the reaction atmosphere. At low CO concentrations, in the absence of COad surface blocking, the selectivity always increases with decreasing Ru particle size, reflecting an inherently low activity for CO2 dissocia-tion of small Ru particle