Thermochemical performance of ceria coated-macroporous 3D-printed black zirconia structures for solar CO/H2 fuels production

The use of macroporous structured ceria for the solar thermochemical splitting of CO2 and H2O to produce clean fuels through two-step redox cycles was investigated. The research aimed to assess the reactivity of 3D-printed black zirconia gyroid structures coated with a microporous layer of pure CeO2 for producing CO and H2. Such porous designs are intended to increase both the absorption of solar radiation and the available surface area for the solid-gas reaction. It was observed that the structure degraded more at the top of the reactor cavity, where the formation of CexZr1−xO2 solid solutions occurred at the coating/substrate interface. Besides, the porous ceria structure remained after redox cycles in the samples not directly exposed to solar radiation. Consequently, the solar reactor achieved CO and H2 production rates of up to 5.4 and 1.9 mL min−1 g−1 with fuel yield over 0.2 mmol g−1, and the material maintained its performance over several consecutive cycles without any loss of reactivity. This indicates a strong potential for producing solar fuels at a large facility using custom 3D-printed ceria-coated structures. [Display omitted] •Porous black ZrO2 structures coated with CeO2 were investigated for CO/H2 production.•3D-printed cubes were subjected to thermochemical cycles in a solar-heated reactor.•The porous hierarchical-ordered structures enhanced the thermochemical reactor performance.•Temperature increase or pressure decrease on reduction favored fuel yield.•Peak CO and H2 fuel production rates of 5.4 and 1.9 mL min−1 g−1 were reached.