Materials Used for Solar Thermal/Thermochemical Processes for CO 2 / H 2 O Dissociation/Conversion

Development of commercially viable renewable energy conversion processes has become one of the major goals of the global research community. The high temperature poses challenges in hydrogen–oxygen high-temperature separation. Effusion and electrolytic separations are two ways to separate hydrogen from the products. The thermochemical cycle may consist of two or more steps. In most cases, the required maximum temperature decreases when more steps are employed, but the energy efficiency also decreases because of the energy losses associated with each step. General Atomics initially introduced the S–I cycle in 1974 on an experimental scale. In addition to two-step thermochemical cycle and S–I cycle, there are a number of other multi-step thermochemical cycles developed for H 2 O/CO 2 splitting/conversion.