(4cb) Interfaces in Thermal-Catalysis and Electro-Catalysis: Methodological and Conceptual Challenges in Connecting Two Worlds | AIChE

(4cb) Interfaces in Thermal-Catalysis and Electro-Catalysis: Methodological and Conceptual Challenges in Connecting Two Worlds


Shih, A. - Presenter, Leiden University
Research Interests:

The vision of my future research group will be the discovery and elucidation of relationships between catalysts and the reactions they catalyze. How do atoms come together and why do they come together the way they do? Transformation of molecules is at the core of energy and environmental chemistry and an understanding of how they transform at the atomic level accelerates progress in catalyst development. As such, research thrusts will be chosen due to environmental impact, industrial importance, and potential for the ideas and theories of the chemistry to be generalized and applicable across disciplines. In particular, we will obtain invaluable insights into the fundamental interfacial processes involved in both thermal heterogeneous catalysis and electrocatalysis. To achieve this, my research group will leverage our expertise in reaction kinetics and operando spectroscopy. Furthermore, we will also collaborate with others whose expertise compliments our own - for instance, with computational groups, groups with expertise in specialized synthesis or characterization techniques, and synchrotron facilities at national laboratories.

Postdoctoral Research: Leiden University, Leiden Institute of Chemistry, Advisor: Marc T.M. Koper

“Electrocatalysis Under Cover: Enhanced Hydrogen Evolution via Defective Graphene Covered Pt(111)”

My postdoctoral research involved studying the mechanism of the hydrogen evolution reaction (HER) in aqueous H2SO4 on Pt(111) and Graphene/Pt(111) electrodes under ambient temperatures and pressures. Graphene was grown on a Pt(111) surface using chemical vapor deposition (CVD) and characterized using scanning electron microscopy (SEM) and Raman spectroscopy. Cyclic Voltammogram (CV) sweeps indicated that the Graphene/Pt(111) electrode is selectively permeable to H+ ions in the electrolyte, allowing only H+ ions into the confined layer between Pt(111) and graphene. The impact of this confinement on the HER mechanism was probed using reaction kinetics (rates, Tafel slopes, reaction orders) where it was found that defects in the graphene are necessary to remove transport limitations, ultimately resulting in G/Pt(111) HER currents that exceed bare Pt(111) by up to 2 times.

During my postdoc, I refined my skillset in collecting and interpreting reaction kinetics in both gaseous and aqueous systems and contemplated differences in the theories between thermal-activated and electron-activated catalysis. In both my PhD and postdoctoral research, probing and understanding how the solvation environment and flow of electrons affected reactivity was essential in rationally piecing together mechanistic details.

PhD Research: Purdue University, School of Chemical Engineering, Advisor: Fabio H. Ribeiro

“Synthesis and Characterization of Copper-Exchanged Zeolite Catalysts and Kinetic Studies on NOx Selective Catalytic Reduction (SCR) with Ammonia”

My PhD research involved unraveling atomic details of the mechanism for model Cu-SSZ-13 zeolite solids to reduce NOx from diesel engine exhaust with NH3 and O2 to environmentally benign H2Oand N2. This research involved collaboration with computational groups (Schneider Group from the University of Notre Dame and Greeley Group at the Purdue University), industrial partners (Cummins Incorporated), Argonne National Laboratory, and international partners (Universidad de Antioquia, Colombia). We first determined from kinetic and spectroscopic evidence that precursors to the active sites were Cu2+ ions, and that even though the material is a solid catalyzing a gas phase-reaction, the Cu2+ behaves as if it is in a liquid solution. Additional quantitative spectroscopy, titration experiments, and density functional theory (DFT) computation confirmed the presence of two types of active Cu2+, namely bare Cu2+ and (CuOH)1+. Computational insight in addition to operando, in-situ, and ex-situ x-ray absorption spectroscopy (XAS) experiments at the Advanced Photon Source at Argonne National Laboratory provided oxidation-state and coordination information, which were used to piece together how these active Cu2+catalyzed the reaction.

Teaching Interests:

My teaching experience includes being a guest teaching assistant for the undergraduate organic chemistry laboratory at Leiden University, teaching fellow twice for the undergraduate fluid mechanics course at Purdue University, a structured study group leader for the undergraduate general chemistry course at the University of Michigan and a tutor for the undergraduate material and energy balances course, also at Michigan. During my studies at the University of Michigan, I developed educational materials with Professor H. Scott Fogler for his textbooks “Elements of Chemical Reaction Engineering, 5th Edition” and “Strategies for Creative Problem Solving”. I also took a 3-credit Educational Methods in Engineering course with Professors Phillip Wankat and Matthew Ohland at Purdue University and attended a workshop hosted by Professors Richard Felder and Rebecca Brent.

I am competent to teach any core chemical engineering course and would like to develop a 1-credit “Design and Construction of Tubing and Piping Systems” course targeted for senior undergraduates and first-year graduate students if facilities and funds are available. To tie my research into teaching, I am enthusiastically willing to teach or develop a course in materials characterization and reaction kinetics in catalysis targeted for first and second-year graduate students. I believe that a display of enthusiasm and joy of learning will engage and motivate students throughout courses. Giving students more responsibility will increase my teaching efficiency while ensuring that the students are challenged, simultaneously allowing me to retain time required to maintain my research group and scientific output.

Diversity Viewpoint:

Diversity supports resilience and facilitates work where several perspectives combine to create something strong and robust. Though diversity about gender and race dominate headlines, other forms of diversity such as skillset, nationality, generation, and much more are also important. In an increasingly globalized world, the need to be proactive in fixing the leaky pipeline for all those who wish to explore the world through science is ever so strong. During my PhD, I mentored two students from the Universidad Nacional de Colombia (one of whom just earned her PhD from Sorbonne Université) in addition to four high school teachers (three from Indiana and one from from the Navajo Nation in New Mexico). Overall during my PhD and postdoc, I worked with researchers from at least 18 nations, each with their unique experiences and ways of living and seeing the world. From these experiences, I observed first hand that different viewpoints from a diverse group of scientists not only challenge outdated assumptions, but also ask questions that would otherwise been overlooked.