Stepping toward the carbon circular economy (CCE): Integration of solar chemistry and biosystems for an effective CO2 conversion into added value chemicals and fuels

Abstract

The substitution of fossil-C is an urgent task for both the scarcity of resources and stopping the emission of green-house gases, (GHGs) that impact the climate of our planet. The transfer to the atmosphere of heat, due to the inefficiency of conversion of chemical energy into other forms of energy, and CO 2 is also causing the increase of atmospheric water vapor, a stronger and more abundant greenhouse gas than CO 2 : all actors (heat, CO 2 and H 2 O v ) concur to increase the temperature of the planet. Partial substitution of fossil-C can be achieved by using biomass, but that alone cannot produce all the energy and goods necessary for our society. Carbon will still be present in our future, but the solution to our problems is integrating solar chemistry and biotechnologies for using atmospheric CO 2 . This chapter, after an introduction to Carbon Circular Economy-CCE and CO 2 utilization in Chemical Industry, considers the various options available of using solar energy for CO 2 conversion into energy vectors that may allow to continue to use the existing infrastructures in transport and every-day life. Two options are considered: (i) solar-based water splitting and use of H 2 for chemo-catalytic CO 2 conversion using known processes, or (ii) photo-co-processing of water and CO 2 to afford energy products and chemicals without H 2 generation, a most innovative technology. The state of the art is provided and barriers to overcome for a large-scale exploitation of the two options are highlighted. The contribution to fossil-C substitution that may come from integration of solar chemistry with material science and biotechnology concludes this chapter.