Numerical and experimental investigation of a two-stage thermochemical water-splitting reactor based on a cerium oxide reduction–oxidation cycle

Climate change has made clear the need to decarbonize the global energy matrix, and green hydrogen has emerged as a promising alternative fuel. In this framework, this work investigates the green hydrogen production by means of a two-stage thermochemical water-splitting reactor heated by both a parabolic dish receiver and a photovoltaic heater. A mathematical model is proposed to simulate reduction–oxidation process for the solar-powered reactor composed of a porous cerium oxide medium. Experimental and numerical thermal profiles show good agreement, with a high temperature in the reduction stage (>1100 K) and a lower temperature in the oxidation stage (860–715 K). Green hydrogen productions show maximum values close to 100 ppm and 2000 $\mu mo{l}_{H_{2}O}/g_{Ce{O}_2}$, for experimental and numerical tests, respectively. It is concluded that the photovoltaic heater is more relevant than the solar concentration heater, and that green hydrogen production could be improved by allowing longer residence times for the reduction–oxidation stages.