Production and usage of solar liquid fuels
Shunichi Fukuzumi
Ewha Womans University, Korea
Meijo University, Nagoya, Japan
: Expert Opin Environ Biol
Abstract
Sustainable and clean energy resources using solar energy are urgently required in order to solve global energy and environmental issues. This lecture focuses on the combination of production of liquid fuels such as formic acid, methanol, and hydrogen peroxide using solar energy, so called solar liquid fuels, and their use in direct liquid fuel cells. In particular, photocatalytic production of hydrogen peroxide (H2O2) from seawater and dioxygen (O2) in the air as a solar fuel is combined with its use in one compartment hydrogen peroxide fuel cells. We have developed a variety of photosynthetic reaction center models composed of organic electron donors and acceptors linked by covalent or non-covalent bonding, which undergo efficient charge separation and slow charge recombination. The efficient charge-separation step has been successfully combined with the catalytic water reduction step with earth-abundant metal catalysts to develop efficient photocatalytic hydrogen evolution systems. The photocatalytic oxidation of water with O2 in the air to produce H2O2 has been achieved, together with the development of H2O2 fuel cells. The photocatalytic oxidation of water with O2 in the air was found to be enhanced significantly in seawater. Thus, the combination of the photocatalytic H2O2 production from seawater and O2 using solar energy with one-compartment H2O2 fuel cells provides on-site production and usage of H2O2 as a more useful and promising solar fuel than H2.