Materials with hierarchical porosity for energy storage and conversion

Two redox systems, i.e., lithium-ion batteries and sunlight-to-fuel conversion, in which templated porous materials provide a platform for either electrical energy storage or light-to-chemical energy conversion, were studied. The role of pore architecture in carbon-based electrodes was discussed. In the second system, the role of porosity in ceria-based materials of interest for solar thermal splitting of water or CO ₂ to produce hydrogen or CO fuels, respectively, was examined. In the reactions targeting the production of chemical fuels (H ₂ and CO) from water and CO ₂, the heterogeneous conversion processes benefited from the added surface area in samples that facilitate the oxidation cycle. The addition of porosity improved peak fuel production rates and reactivities. However, a mesoporous ceria sample displaying an even higher surface area quickly lost activity as the material sintered during the reaction. The interplay between composition and morphology of these materials, thermal stability, and conversion efficiencies were discussed. This is an abstract of a paper presented at the 2011 AIChE Annual Meeting (Minneapolis, MN 10/16-21/2011).