Hydrogen addition catalysis involves the activation of molecular H2 that forms reactive hydrogen species, before their sequential attack to organic substrates in hydrogenation and hydrodeoxygenation reactions. These reactions are of industrially importance for the synthesis of sustainable fuels and value-added products. In this lecture, I will introduce the concepts of designing active site structures and local reaction environment that would alter the electronic charges of the reactive hydrogen as well as the organic substrates of carbonyls and phenolics and in turn the stability of the transition state and the resulting turnovers, illustrated here for the case of hydrodeoxygenation of 3-methoxyphenol, as well as the reduction of carbonyls, and with phenol deuteration as the probe reaction. Through tuning of reaction environments with protic solvents, the reactive hydrogen on transition metal surfaces could act as either hydride or proton and therefore acquire multiple catalytic roles in the hydrogen addition events during hydrogenation and hydrodeoxygenation. The acidity of the hydrogen depends on the metal identity (through its work function), the hydrogen binding energy, and the properties of solvent. Similarly, the tuning could also mediate the charge and stability of the carbon containing precursors and transition states. These effects have marked catalytic consequences, as they reshape the free energy landscape of the reaction, change the reaction mechanism, and alter the catalytic fate of the organic substrates. The engineering of active site structure and local reaction environment allows us to manipulate reaction pathways, therefore optimize the yields.
Ya-Huei (Cathy) Chin is Professor and Canada Research Chair (Tier II) in Advanced Catalysis for Sustainable Chemistry at the University of Toronto. She joined the University in 2011, after receiving her Doctor of Philosophy (Ph.D.) degree in Chemical Engineering from the University of California, Berkeley. Before then, she was a research engineer (2000-2002) and then senior research scientist (2002-2005) at Pacific Northwest National Laboratory (PNNL), one of the ten National Research Laboratories for the U.S. Department of Energy.
Her recent work focuses on drawing mechanistic linkages for catalytic events during alkane oxidation on Group VIII metal clusters and conversion of oxygenates to value-added chemicals and liquid fuels. Specifically, she applies isotopic, kinetic, and density functional theory methods to study the dynamics of catalyst surfaces and catalytic pathways for reactions at the vapor-solid and liquid-solid interfaces.
She serves as an editor for the Journal of Catalysis and as an advisory board member for several premier journals of the field, including Applied Catalysis B: Environmental, Reaction Chemistry and Engineering, Chem Catalysis, and Canadian Journal of Chemical Engineering.