Structure and Dynamics in Heterogeneous Reactions

Princeton University, Princeton NJ

Investigators

Abstract

NON-TECHNICAL SUMMARY The focus of the research supported in this project is to gain a fundamental understanding of the connection between the atomic and molecular structure and composition of surfaces and interfaces, and the chemical properties and reactivity of these interfaces. A large number of important technologies, ranging from the use of catalysis in the production of chemicals and fuels, to the processing of electronic components, to the prevention of corrosion and structural deterioration, depend on an understanding of the structure and reactivity of surfaces and interfaces. Four particular research topics are contained in this project. The first explores the detailed molecular dynamics of catalytic oxidation reactions important in pollution control and chemical production. The second is concerned with mechanisms of surface oxidation and corrosion of structural metals and strategies for its prevention. The third explores the microscopic mechanism of the process of self-assembly at surfaces, relevant to the production of next generation electronic devices and the understanding of bio-films and membranes. The fourth topic seeks to develop methods for the detailed analysis of the complex surfaces and interfaces that are the subject of this research project. Each of these research topics serves to train students in research methods while providing the fundamental knowledge to support a wide array of technologies. TECHNICAL SUMMARY This research project focuses on the connection between the detailed atomic, molecular, and electronic structure of surfaces and interfaces, and their chemical properties and reactivity. These fundamental questions of surface structure and reactivity are addressed in four interrelated areas. Studies of catalytic oxidation focus on the implementation of nanoplasmonic sensors to evaluate the coverage and presence of intermediates on the catalyst surface during heterogeneous catalytic oxidation reactions. Mechanistic information obtained from these measurements will be coupled with product internal state distribution information obtained by diode laser absorption spectroscopy, to provide a more complete picture of the catalytic oxidation reaction dynamics. The second area addresses structural alloy oxidation in extreme environments, and synergistic effects in mixed molecular corrosion inhibitors, using photoelectron spectroscopy and electrochemical analysis of the surfaces. The third area concerns the mechanisms of self-assembly of large organic molecules at the liquid-solid interface, with a focus on the synthesis of fundamentally interesting chemisorbed self-assembled monolayers (SAMs), and the quantitative evaluation of the energetics of formation of physisorbed SAMs on graphite. Work in the fourth area develops methods to use both static and dynamic differential charging in X-ray photoelectron spectroscopy to enable the chemical and electronic property analysis of complex composite surface materials that are the focus of the previous research topics.