Solar fuels may be produced from two-step reduction-reduction (redox) cycles much like thermochemical energy storage (TCES). Solar fuels allow for the efficient storage of concentrated sunlight in a stable, useful form, and may expand the benefits of solar technologies to the transportation sector.
Solar Fuels Cycle
In solar fuels production via redox methods, gas streams of CO2 and/or H2O are exposed to a reduced metal oxide. Under favorable thermo-dynamic conditions, the gases react with the metal oxide and split, increasing the oxidation state of the metal while forming CO and/or H2. The H2/CO mixture is termed synthesis gas, and can be used as an energy storage medium or further processed via catalytic methods such as the Fisher-Tropsch process to produce conventional liquid fuels. The oxidized metal may then be exposed to concentrated sunlight to promote thermolysis, closing the redox cycle and reforming the metal oxide for further use in producing solar fuels.
The Solar FTL is interested in the development of reactor technology and redox materials to produce solar fuels. These include previously studied systems such as ZnO/Zn and Fe3O4/FeO, nonstochiometric CeO2-δ, and novel synthetic materials with finely-tuned thermodynamic and kinetic properties for optimal reaction behaviors and cycle efficiencies.
For more information on the Solar FTL’s solar fuels research, please see our following publication:
