Precursor salts influence in Ruthenium catalysts for CO2 hydrogenation to methane

The intermittency in power generation that characterizes renewable energy sources requires a way to convert the energy surplus. Among all the possibilities, the conversion of power in hydrogen via water electrolysis and then into methane via CO2 methanation represents a competitive storage system. CO2 methanation is an exothermic reaction which requires the use of low temperatures in order to achieve sufficiently high conversions: for this reason, there is a strong need in low-temperature active catalyst. In this work, several Ru/CeO2-ZrO2 and Ru-Ni/CeO2-ZrO2 were prepared and compared with Ni/CeO2-ZrO2, in order to evaluate the effect of Ru loading and Ru precursor salt. The results showed that in monometallic formulations the higher was the Ru amount the better were the reaction performances achieved, particularly at low temperatures. In bimetallic formulations, the presence of Ru enhances the catalyst activity; in particular, the use of the Ru acetylacetonate, for the deposition of the noble metal on support, remarkably reduces the catalyst onset temperature. The effect is due to the templating effect of the precursor molecule, which allows a better dispersion of the active compounds.