Computational Studies of Nonequilibrium processes in Electrochemical Materials Science

Florida State University, Tallahassee FL

Investigators

Abstract

TECHNICAL SUMMARY: This award supports research and education in computational and theoretical studies of nonequilibrium phenomena in electrochemical materials science. These studies are concerned with modeling of specific experimental systems, with investigation of fundamental nonequilibrium phenomena of importance to such systems, and with further development of computational and theoretical methods. The particular experimental phenomena, which will be investigated in collaboration with experimental groups, are island growth and dissolution in electrochemical pulsed-potential studies of single-crystal gold surfaces, and verification of a new method to study the dynamics of electrode surfaces that was suggested by the PI's computer simulations. Particular nonequilibrium phenomena that are investigated include the influence of lateral diffusion during electrochemical metal deposition and in heterogeneous catalytic reactions, and hysteresis in systems that are driven far from equilibrium by an oscillating force. The main method that will be used in the proposed research is large-scale computer simulation of model systems. Both continuous and discrete models will be used, and the computational methods will include kinetic Monte Carlo (KMC) simulations and numerical solution of stochastic differential equations, both with model parameters obtained from quantum-mechanical density-functional-theory calculations. The simulation data will be analyzed using several theoretical methods, including finite-size scaling theory, theory of stochastic processes, and statistics. The research has broader impact beyond the particular scientific investigations undertaken and contributes broadly to understanding issues of nonequilibrium processes and is relevant to technological development and has educational benefits. Since all time-dependent phenomena in nature, as well as in technology, are out of equilibrium by definition, nonequilibrium statistical mechanics is an essential research area. This research adds to our fundamental understanding of nonequilibrium processes. More specifically, this research improves understanding of nonequilibrium processes at electrode-electrolyte interfaces, and thereby contributes to the future development of new, electrochemistry-based manufacturing processes for advanced nanomaterials. Such fundamental knowledge and simulation algorithms developed through the research are applicable in many scientific and technological fields, including materials science, chemistry, biology, and even to the design and analysis of communications networks and power grids. This computationally intensive research is ideal for involving apprentices at all levels in the discovery process. It will contribute to education at all levels while including women and minorities by involving undergraduate and graduate students and postdoctoral fellows, who will mentor K-12 students. The results of the research will be communicated through articles in a wide spectrum of professional journals, through talks at scientific meetings, and through presentations for the general public, as well as through the World Wide Web. NONTECHNICAL SUMMARY: This award supports theoretical and computational research, and education on the growth of materials and structures of atoms on the scale of nanometers, about one ten-millionth of an inch, by electrochemical methods. During the last two decades experimental techniques have become available that enable electrochemical methods to manufacture high-tech materials that derive their functionality from structure on the nanometer scale. These methods are rapidly becoming cost-effective alternatives to traditional methods. These impressive experimental developments are matched by spectacular progress in computer technology and computational methods. The PI will use computer simulation methods to study how nanoscale structures grow on the surface of electrode materials immersed in a chemical solution with an electric current flowing through the electrodes. The study of growth phenomena like these advances the understanding of phenomena that are intrinsically out of equilibrium, an area of intense interest in modern statistical physics. Since all time-dependent phenomena in nature, as well as in technology, are out of equilibrium by definition, nonequilibrium statistical mechanics is an essential research. This computationally intensive research is ideal for involving apprentices at all levels in the discovery process. It will contribute to education at all levels while including women and minorities by involving undergraduate and graduate students and postdoctoral fellows, who will mentor K-12 students. The results of the research will be communicated through articles in a wide spectrum of professional journals, through talks at scientific meetings, and through presentations for the general public, as well as through the World Wide Web.