Correlation of Catalytic Activity to Material Structure and Surface Composition for Sustainable Catalysis

Abstract

This thesis investigates the relation between the catalytic activity and catalyst material to develop a predictive framework for the rational design of catalytic systems. More specifically, catalyst morphology, surface structure, and surface composition are probed to understand their impact on catalyst activity and selectivity for sustainable catalysis applications. We begin with an introduction of sustainable catalysis, with an emphasis on the use of copper catalysts and alloy materials (Chapter 1). The details of the methods used in this thesis are then presented (Chapter 2). Next, the role of defects and step edge sites in elementary reaction steps is studied for methanol oxidation on titania (Chapter 3) and ethanol dehydrogenation on copper (Chapter 4). The study of ethanol dehydrogenation reaction is further expanded to understand the effect of alloying nickel with copper materials on the catalyst activity and selectivity (Chapter 5). A thorough investigation is undertaken to understand surface compositional (Chapter 6) and structural (Chapter 7) changes induced by different gas exposures of a nanoporous nickel-copper catalyst. The changes in surface composition and structure using in situ techniques are correlated to changes in catalytic activity and stability (Chapters 6 – 7). The use of reactive gases to alter catalytic materials is further investigated on a bulk silver-gold alloy as a model for nanoporous gold catalysts (Chapter 8).