CO2 reduction with Zn particles in a packed‐bed reactor

A two‐step solar thermochemical cycle for splitting CO2 with Zn/ZnO redox reactions is considered, consisting of: (1) the endothermic dissociation of ZnO with concentrated solar radiation as the heat source and (2) the non‐solar, exothermic, reduction of CO2 to CO by oxidizing Zn to ZnO; the latter is recycled to the first step. The second step of the cycle is investigated using a packed‐bed reactor where micron‐sized Zn particles were immobilized in mixtures with submicron‐sized ZnO particles. Experimental runs were performed for Zn mass fractions in the range 67–100 wt % and CO2 concentration in the range 25–100%, yielding Zn‐to‐ZnO conversions up to 71% because of sintering prevention, as corroborated by SEM analysis.