"The research is aimed at the efficient production of solar fuels from H2O and CO2. Solar thermochemical approaches using concentrating solar energy inherently operate at high temperatures and utilize the entire solar spectrum, and as such provide thermodynamic favorable paths to efficient solar fuel production. The targeted solar fuel is syngas: a mixture of mainly H2 and CO that can be further processed to liquid hydrocarbon fuels (e.g. diesel, kerosene), which offer high energy densities and are most convenient for the transportation sector without changes in the current global infrastructure. The strategy for the efficient production of solar syngas from H2O and CO2 involves research on a 2-step thermochemical redox cycle, encompassing: 1st step) the solar-driven endothermic reduction of a metal oxide; and 2nd step) the non-solar exothermic oxidation of the reduced metal oxide with H2O/CO2, yielding syngas together with the initial metal oxide. Two redox pairs have been identified as most promising: the volatile ZnO/Zn and non-volatile CeO2/CeO2-δ. Novel materials, structures, and solar reactor concepts will be developed for enhanced heat and mass transport, fast reaction rates, and high specific yields of fuel generation. Thermodynamic and kinetic analyses of the pertinent redox reactions will enable screening dopants. Solar reactor modeling will incorporate fundamental transport phenomena coupled to reaction kinetics by applying advanced numerical methods (e.g. Monte Carlo coupled to CFD at the pore scale). Solar reactor prototypes for 5 kW solar radiative power input will experimentally demonstrate the efficient production of solar syngas and their suitability for large-scale industrial implementation. The proposed research contributes to the development of technically viable and cost effective technologies for sustainable transportation fuels, and thus addresses one of the most pressing challenges that modern society is facing at the global level."