(203c) Two Step Solar Thermochemical CO2 Splitting with CoFe2O4 On Porous Al2O3 Nanostructure

Arifin, D. - Presenter, University of Colorado Boulder
Aston, V. J., University of Colorado at Boulder
Weimer, A. W., University of Colorado at Boulder

Projected growth in global population and continued industrialization of developing countries will increase total world energy consumption by 50% in the next three decades. This increased demand for energy will be largely met by increased fossil fuel consumption, thereby increasing anthropogenic carbon in the atmosphere and further fuelling geopolitical conflicts over control of dwindling energy resources. Recycling CO2 by splitting it in a solar-based thermochemical process is an attractive solution to both of these 21st century problems.

In this work, we examine a novel chemistry for a two-step, non-volatile metal oxide CO2 splitting cycle that utilizes the change in iron oxidation states (Fe2+/3+) between CoFe2O4 and FeAl2O4 spinel compounds within a nano-engineered material. This chemistry is dramatically different than current metal oxide cycles that exploit oxygen non-stoichiometry in ceria or solid solution behavior in ferrites. The engineered material was prepared using atomic layer deposition and maintained structural integrity over 10 heating cycles under conditions that mimic a concentrated solar power application, namely an oxidation temperature of 1000°C, reduction at 1460°C, and a heating rate of 16°C/s from low to high temperature. Oxygen uptake and release behavior was similar to that of ceria. Raman spectroscopy was used to verify cycle chemistry.