Sunshine to petrol: Solar thermochemical splitting of carbon dioxide and water

Synthetically producing hydrocarbon fuels from carbon dioxide and water is an attractive option for storing solar energy. Thermochemical approaches to accomplishing this conversion are potentially highly efficient as they avoid the solar-to-electric conversion necessary, for example, to drive electrolysis. We are developing metal oxide-based two-step thermochemical cycles for splitting CO₂ and H₂O to produce CO and H₂, the universal building blocks for synthetic fuels. Concentrating solar power provides a means to the ultra-high temperatures required. Working metal oxides have been fabricated into robust monolithic structures and evaluated in the laboratory and on-sun at the National Solar Thermal Test Facility. We will report on the demonstration of the solar-driven production of H₂ and CO over several iron- and cerium-based compositions. Thermodynamic analyses of reactions and processes and progress towards demonstrating the reactions in a unique and continuous solar-driven reactor, the counter-rotating-ring receiver reactor recuperator or CR5 will also be reported.