Additive manufacturing and two-step redox cycling of ordered porous ceria structures for solar-driven thermochemical fuel production

This study focuses on thermochemical H2O and CO2-splitting processes using non-stoichiometric metal oxides concentrated solar energy to produce fuels. The redox process involves two distinct reactions: (i) a thermal reduction at high temperature of the oxide with creation oxygen vacancies in its crystallographic structure, resulting released O2; (ii) re-oxidation by and/or CO2, yielding H2 CO. Hierarchically-ordered porous ceria materials offer potential for solar-driven fuel production based two-step cycles CO2-splitting. emergence additive manufacturing allows develop architected reactive 3D-ordered geometry hierarchical structure (porosity gradient), able enhance volumetric absorptivity provide homogeneous heating carrier. investigation additive-manufactured ordered monoliths made from 3D-printed polymer scaffolds was performed reactor. In comparison reticulated foams, an improvement yields achieved structures. A low total pressure during step (inducing pO2) favored extent associated yields. rate exothermal oxidation enhanced decreasing increasing CO2 partial pressure. addition, since is surface-controlled reaction, natural pore former (woody biomass) used create µm-size pores within struts scaffolds. kinetics maximal CO 4.9 mL/min/g yield up 333 µmol/g (with 1400 °C under ~0.10 bar pressure). Thus, open-cell addition micro-scale porosity performance.