Pushing the Limit of Electrochemistry Towards Single Atoms and Molecules
Abstract
The proposed two-year research program is aimed at developing innovative molecular-level simulations and experimental methods for in,vestigating electrochemical phase transitions and ET transferre actions at nanoscale structures, including measurements at particles, of sub-nanometer dimension. These methods will be used to address basic science questions and are likely transferable to applicatio,ns inelectrochemical research beyond the investigations proposed here. The proposed work is specifically focused on two efforts: (i), the wrap-up of our current program on gas-phase nucleation and nanobubble electrochemistry, and (ii) the initiation of a new progra,m tomeasure heterogeneous electron-transfer atindividual metal atoms and clusters.Our research efforts on gas-phase nucleation durin,g the past funding period focused on development of experimental methods to measure the kinetics of the nucleation of nanobubbles, l,eading to the first determination of the critical gas nucleus size, nucleation activation energy, and number of molecules contained, within the nucleus. We relied on classical nucleation theory (CNT) to extract these parameters. The proposed program on nanobubbles, now focuses on the application of these methods to examine three specific issues: (1) the dependence of nucleation on temperature;, (2) the influence of electrode properties (hydophilicity) and surface defects (e.g., crevices) on nucleation; (3) and whether phase, transitionsv can be catalyzed by sub-nanometer particles. The proposed program includes the addition of atheorist, Dr. Valeria Moli,nero, who has extensive experience and expertise in molecular simulations of phase transitions. Theoretical investigations of electr,ochemical nucleation from her research group are integrated with the proposed experimental studies. A molecular simulation framework, that enables the modeling of electrochemical reactions on electrodes of arbitrary shape and size will be developed in this research,, which will be used to elucidate the fate of the solution during bubble phase transition at sub criticalsized electrodes, the nucle,ation and stationary states of bubbles, and the roles of topography, catalytic and wetting heterogeneity on the nucleation.In additi,on to the investigations of nanobubbles, we propose to explore the dependence of electron transferkinetics for simply outer-sphere r,edox reactions as a function of the size of the metalatom/cluster/particle size. The Marcus-Gerischer microscopic model of electron-,transfer kinetics explicitly expresses the ET rate in terms of the density of electronic states on the electrode, which would be a f,unction of particle size for particles smaller than ~2 nm. Thus, we anticipate seeing a marked decrease in ET rates as the particle, size is decreased. These studies will provide a baseline for future work on the dependence of rates of technologically important el,ectrocatalytic reactions on particle size.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 08, 2022
- Source ID
- N000142212425
Entities
People
- Henry S. White
Organizations
- Office of Naval Research
- United States Navy
- University of Utah