Professor Daniel A. Buttry of Arizona State University is supported by the Division of Chemistry to study the effect of size and surface stress on the electrochemical properties and phase transformations of metal and metal oxide nanoparticles; in particular, Ag oxidation to AgCl, Pd reduction to PdHx and layered LixMnO2 conversion to spinel LixMn2O4. Methods will be developed for the facile synthesis and size fractionation of Ag, Pd and MnO2 nanoparticles with controlled sizes in the range of 1.5 - 10 nm. The particles will be capped with adenosine triphosphate (ATP) to facilitate their dissolution at high concentration in aqueous supporting electrolytes, thus enabling the study of their electrochemical behavior in thin layer-by-layer films and as individually dissolved nanoparticles. The particles will be subjected to a battery of analytical characterization techniques to determine their sizes and composition. Surface stress will be determined from lattice contraction measurements.
The use of nanoscale materials has become widespread in electrochemical energy storage and conversion; however, the basic understanding needed to advance new technologies in this area is lacking. This research will develop a set of experimental systems that can provide a basic thermodynamic understanding of nanoscale size effects in electrochemistry, especially in processes involving phase transformations. Students will be trained in techniques that are relevant to energy storage and conversion, and secondary science teachers will be exposed to a summer research experience.
