Abstract
The depletion of fossil fuels increased the interest towards the power-to-gas technologies for the conversion of energy excess (such as photovoltaic energy) in valuable chemicals. In this direction, the CO2 hydrogenation to substitute natural gas strikes the double target to reduce a greenhouse emission and to exploit solar energy surplus. These papers addressed on the study of innovative catalysts for the CO2 hydrogenation (Sabatier reaction), by paying attention on the role of active phase and chemical support. In particular, the effect of nickel loading was investigated, evidencing that in one hand the higher amount of active specie increased the activity and reduced the onset temperature of the catalyst, in the other hand too large loadings could suppress the dispersion of the metal, thus reducing the CO2 conversion. The employing of ceria and ceria-zirconia as catalytic supports improved the sample reducibility, so increasing the CO2 conversion and reducing the activation temperature of the catalytic system; in particular, CeO2-ZrO2 sample showed a higher selectivity towards the Sabatier reaction. The high exothermicity of the reaction is better managed by employing highly conductive structured catalysts that assured an enhanced redistribution of the heat in the whole reaction volume, thus assuring higher conversion values and mainly higher selectivity towards methane production.
