Thermochemical Transformations Using Entropy-Stabilized Oxides
Abstract
Thermochemical Transformations Using Entropy-Stabilized OxidesAbstractEntropy-stabilized oxides (ESOs) are a recently discovered class of materials that offer tworemarkable attributes: (a) unprecedented ability to tune the enthalpy and entropy of bound oxygen in the solid phase; (b) possibly unique arrangements of co-located neighboring transition metal cations in metastable crystal str"uctures. The first attribute could potentially offer new pathways for thermochemical redox reactions. As an example, preliminary wor"k on watersplittingreactions using a four-cation ESO has produced a remarkable breakthrough in reducing the temperature of hydrogen" production to 1100 oC, which is beyond the reach of traditional oxides such as ceria and ferrites that operate >1300 oC. We propose"" leveraging this attribute to explore the possibility of CO2 reduction to form CO, a well-known precursor for chemical synthesis. Th"e second attribute offers the promising prospects of cooperative effects in catalysis using multiple neighboring transition-metal ca"tions. Here, one cation could be used to chemisorb a chemical species while the others in the neighborhood could be used to stabiliz""e a complex via physisorption or chemisorption. Such multi-cation catalysis is found in biological enzymes, butsimilar mimics in in"organic catalysts have remained largely elusive. We will explore whether ESOs could potentially offer this promise in both Fischer-T"ropsch hydrogenation of carbon as well as C-H bond activation, which remains as one of the most difficult reactions to control. We w""ill leverage collaborations with the computational group at Stanford to guide the choice ofmulti-cation combinatorics of ESOs, and"" then synthesize these materials to experimentally study their impact on chemical transformations. Furthermore, we will use X-ray ab"sorption spectroscopy at SLAC to determine the role of the oxygen and the metal cations in thesechemical transformations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 29, 2017
- Source ID
- N000141712918
Entities
People
- Arun Majumdar
Organizations
- Office of Naval Research
- Stanford University
- United States Navy