Artificial photosynthesis: biomimetic approaches to solar energy conversion and storage

Using sun as the energy source, natural photosynthesis carries out a number of useful reactions such as oxidation of water to molecular oxygen and fixation of CO2 in the form of sugars. These are achieved through a series of light-induced multielectron-transfer reactions involving chlorophylls in a special arrangement and several other species including specific enzymes. Artificial photosynthesis attempts to reconstruct these key processes in simpler model systems such that solar energy and abundant natural resources can be used to generate high energy fuels and restrict the amount of CO2 in the atmosphere. Details of few model catalytic systems that lead to clean oxidation of water to H-2 and O-2, photoelectrochemical solar cells for the direct conversion of sunlight to electricity, solar cells for total decomposition of water and catalytic systems for fixation of CO2 to fuels such as methanol and methane are reviewed here.