438519 Thermochemical Cycles for the Production of Essential Chemicals

Sunday, November 8, 2015
Exhibit Hall 1 (Salt Palace Convention Center)
Timothy Davenport, Materials Science, California Institute of Technology, Pasadena, CA

Solar-driven thermochemical water splitting has received significant recent attention for solar energy storage because of its potential for high solar-to-fuel conversion efficiency and, when deployed using nonstoichiometric oxides, its chemical simplicity. One particularly attractive approach uses ceria as the reactive medium due to its rapid reaction kinetics, which has been attributed to its nonstoichiometric behavior and fluorite structure. My research program will focus on the development of novel energy efficient thermochemical cycles based on nonstoichiometric oxides to synthesize other chemicals essential to modern society, such as ammonia and ethylene. Research in the laboratory will emphasize on the synthesis and characterization of new materials, catalysis, and process analysis, combining the fields of materials science, chemistry, and chemical engineering.

Postdoctoral Research:

Advised by Sossina Haile, Department of Applied Physics and Materials Science and Department of Chemical Engineering, California Institute of Technology

Optimization of Fuel Production by Ceria-Based Isothermal Pressure-Swing Cycles under Gas-Flow Limited Kinetics

             In isothermal pressure-swing cycles (in which water-splitting is driven by switching between an inert, reducing gas and an oxidizing gas, such as steam, at a constant temperature) material kinetics of ceria were determined to be so high that the reaction kinetics were limited only by the rate of flow of reducing or oxidizing gas through the reactor.  With knowledge of the gas flow limited kinetics, an integrated kinetic and thermodynamic model was developed with which the optimal fuel production rate could be determined for any possible operating conditions.

 Determination of Thermodynamic Parameters in Doped Ceria Materials

             The enthalpy and entropy of reduction as a function of nonstoichiometry was determined for Pr-doped ceria (for 5, 10, 20, 40, and 60% Pr content) and Tb-doped ceria (for 10% Tb content) by thermogravimetric analysis under varying atmospheres.

 Graduate Research:

Advised by T. Don Tilley, Department of Chemistry, University of California, Berkeley

Dissertation: “Development of Dinuclear Metal Complexes for Catalytic Transformations in Artificial Photosynthesis”

             Dinucleating ligands were designed to coordinate two metal centers with a specific geometry.  This geometry was then tested for catalytic activity towards water oxidation.

Undergraduate Degrees – Massachusetts Institute of Technology

S.B. Chemical Engineering

S.B. Chemistry

Physics - Minor

Extended Abstract: File Not Uploaded