This project aims at demonstrating the utility of the thermal transport by design approach to develop functionally graded reactive materials that allow for fast and efficient solar thermo-chemical fuel production. Prediction capabilities will be developed to optimise multi-scale radiative and gas transport coupled with non-stoichiometric redox reactions. Synthesis gas production will be demonstrated using the new structures in a prototype solar thermochemical reactor under high-flux irradiation. This project will advance the fields of thermal sciences and high-temperature solar thermochemical processing, and expand the engineering knowledge base to pave the way to sustainable transportation while preserving the existing infrastructure.