Improved operation of solar reactor for two-step water-splitting H2 production by ceria-coated ceramic foam device

The joint international project between Niigata University (Japan) and the Korea Institute of Energy Research, KIER (Korea) on “Solar Demonstration of Water-Splitting Reactor using Ceramic Foam Device” has two goals. (1) Develop a solar reactor using reactive cerium oxide foam devices for high-temperature two-step thermochemical water-splitting cycle. (2) Test its performance under various operational methods using a 40 kWth solar furnace driven by natural solar energy. The reactive CeO2/MPSZ (MgO - partially stabilized zirconia) foam device for two-step water-splitting was developed and prepared by Niigata University/Japan; it involves coating an inert zirconia foam matrix with reactive CeO2. In this paper, highly reactive CeO2 particles were used the redox material in CeO2/MPSZ foam devices to investigate the use of solar energy for hydrogen production. The solar-driven thermochemical two-step water-splitting cycle was demonstrated using the 40 kWth KIER solar furnace in Korea combined with the CeO2/MPSZ foam device. At the center of the foam device, temperatures were 1500 °C-1600 °C during the thermal reduction step and 600 °C-1100 °C during the subsequent water decomposition step. Hydrogen was successfully produced from the CeO2/MPSZ foam device, and profiles for hydrogen production and CeO2 conversion indicated definitely improved operations compared to earlier studies.