Insight into CO2 utilization for energetic purposes: the catalytic hydrogenation versus the photocatalytic reduction.

The growing interest toward climate changes and the always increasing emissions of CO2 from industrial plants, have prompted new seeks in the field of technologies for CO2 capture and utilization. In particular, the use of CO2 as source for the synthesis of "eco friendly" energy vectors, through the conversion into fuels, appears one of the most sustainable routes to mitigate the emissions and to cope with the growing energy demand. Therefore, this work is aimed to present a systematic evaluation of the catalytic and photocatalytic conversion processes of CO2 into hydrocarbons, by comparing the performance of three different families of Cu-based materials (i.e. CuZn/Al2O3, FeCu/ Al2O3 and Cu/TiO2). The chemical formulation and the process conditions affect the performance in the synthesis of fuels, determining productivity and products distribution. The energy balance of the three different processes clearly shows that the CO2 photosynthesis is energetically more efficient than catalytic hydrogenation; on the other hand, the catalytic hydrogenation is at the moment most performing choose in term of energy yield and the most suitable route for the industrial exploitation of CO2 as sustainable energy vector.