title: Splitting CO2with a ceria-based redox cycle in a solar-driven thermogravimetric analyzer.
abstract: Thermochemical splitting of CO2via a ceria-based redox cycle was performed in a solar-driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+-doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200-1950 K and subsequently re-oxidized with CO2at 950-1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm-sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm-sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+-doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics.
authors.affiliation: Dept. of Mechanical and Process Engineering ETH Zurich Zurich 8092 Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Takacs
authors.affiliation: Dept. of Mechanical and Process Engineering ETH Zurich Zurich 8092 Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Ackermann
authors.affiliation: Laboratory of Materials for Energy Conversion EMPA Dübendorf 8600 Switzerland; Institute for Geo- and Life Sciences, Crystallography, Albert-Ludwigs-Universität Freiburg Freiburg 79085 Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bonk
authors.affiliation: Institute of Solar Research, German Aerospace Center Linder Höhe Köln 51147 Germany.
authors.forename: M
authors.initials: M
authors.lastname: Neises-von Puttkamer
authors.affiliation: Dept. of Mechanical and Process Engineering ETH Zurich Zurich 8092 Switzerland.
authors.forename: Ph
authors.initials: P
authors.lastname: Haueter
authors.affiliation: Dept. of Mechanical and Aerospace Engineering University of Florida Gainesville FL 32611.
authors.forename: J R
authors.initials: JR
authors.lastname: Scheffe
authors.affiliation: Laboratory of Materials for Energy Conversion EMPA Dübendorf 8600 Switzerland; Institute for Geo- and Life Sciences, Crystallography, Albert-Ludwigs-Universität Freiburg Freiburg 79085 Germany.
authors.forename: U F
authors.initials: UF
authors.lastname: Vogt
authors.affiliation: Dept. of Mechanical and Process Engineering ETH Zurich Zurich 8092 Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Steinfeld
keywords: doped ceria; heat transfer; kinetics; solar fuels; thermochemical