Hybrid (enzymatic and photocatalytic) systems for CO2-water coprocessing to afford energy-rich molecules

This chapter deals with selected aspects of man-made solar-driven photoreduction of CO2. In particular, direct photosynthetic processes are discussed which include the use of man-made materials for solar energy capture and utilization in enzymatically driven CO2 reduction to energy-rich C1 molecules. The enzymatic reduction of CO2 requires cofactors which are the energy vectors to enzymes which in turn reduce CO 2 to energy-rich C1 molecules. The regeneration of the reduced form of such cofactors is a key step in the whole process. The level at which man-made systems may recycle the cofactor and support the reduction reaction is discussed, and barriers to a full exploitation of the option are highlighted. The use of visible light in the entire process is privileged. The paper does not cover other uses of solar energy such as thermal devices (solar power concentrators) nor solar-driven pure electrochemical processes, such as the use of PV for water electrolysis and hydrogen generation employed for CO2 chemical reduction.