(2ei) Design Principles and Mechanistic Understanding of Heterogeneous Catalysis Towards Sustainable Development

Past and Present Research Accomplishments

I graduated from the department of Chemical and Biological Engineering at the Hong Kong University of Science and Technology, Hong Kong in 2020. My expertise primarily involves holistic understanding of electrochemical catalytic processes, that facilitate energy conversion and storage for renewable energy, particularly using novel functional 2D materials. During my Ph.D., I visited California Institute of Technology to work with Prof. William A. Goddard III. During that time, I developed constant potential-based grand canonical potential kinetics (GCP-K) method for the CO₂RR. The resulted paper was published in Nature Communications and featured as one of the top 50 articles in physics in 2020. Later, we extended this method to other 2D electrocatalysts such as TMDs for water splitting applications. Currently as a Postdoctoral Fellow at the SUNCAT center, my research primarily involves an atomistic understanding of catalysts activity, selectivity, and stability for energy conversion reactions application. Our target electrochemical reactions involve hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), CO₂ reduction (CO₂RR) for sustainable energy development.

Future Research

Design principles of electrocatalysis holds a pivotal significance with regards to the electrochemical production of value-added chemicals. I envision to conduct comprehensive study in this field via extensive theoretical studies, which will involve method development, atomistic understanding of electronic properties, and comprehensive insights into reaction mechanism and kinetics. Additionally, I intend to apply machine learning techniques for further activity screening, stability prediction, and optimization of reaction conditions with extensive experimental collaborations.

Proposed Future Goals

Goal 1: Advancing electrochemical approaches for biomass upgrading into valuable chemicals

Challenge 1: Electrochemical biomass conversion reaction to value-added chemicals is considered one of the sustainable alternatives over traditional thermal heterogeneous catalysis technique. Transition metal oxides and oxy-hydroxides show great potential as electrocatalyst for biomass upgrading, however, lack of systematic investigation towards active sites selectivity, controlled electrochemical activity and moreover, robust reaction mechanism limits its industrial applications. It is well known that biomass oxidation (BO) can be activated at equilibrium potential of electrode materials oxidation (M²⁺ to M³⁺), E⁰. Which implies BOR exhibits faster reaction kinetics than oxygen evolution reaction (OER) at ambient reaction conditions, indicating the prospects of alternative anodic reactions in fuel cell electrolyzers. Here, my propose research aims to increase the BOR activity by decreasing electrode potential, E⁰, for a series of 3d-transition metal oxides as a function of surface atomic doping, pH, electric field.

Goal 2: Potential dependent computational study of Urea formation from greenhouse gases and liquid wastes.

Challenge 2: Electrochemical reduction of CO₂ gases (CO₂RR) to value-added chemicals powered by renewable energy, offers an alternative pathway to achieving carbon neutrality. So far, quantum mechanics calculation employs fixed number of electrons, which is unable to simulate exact electrochemical reaction conditions. Here, I propose to apply constant potential method using implicit/explicit solvation implemented in DFT to mimic the real experimental conditions, and to identify reaction intermediates for CO₂RR, NO₃RR along with their co-reduction to urea for various transition metal-based electrocatalysts. The transition state barrier will be calculated by using climbing image nudged elastic band (method), or ab initio molecular dynamics (AIMD) simulations at constant potential. After accurately predicting energy barrier for different transition states, micro-kinetic modeling will be fitted to predict reaction rate, and to derive current-potential relationship.

Goal 3: Understanding of 2D heterostructure growth mechanism and kinetics in CVD using atomistic simulation

Challenge 3: Chemical vapor deposition (CVD) route has emerged as an efficient method to produce large-scale high quality two-dimensional (2D) materials required for various applications. This process has been used vastly to grow 2D materials such as graphene, hexagonal boron nitride (hBN), and transition metal chalcogenides (TMDs). In this regard, modeling and simulation can facilitate in predicting favorable growth conditions as well as providing mechanistic insight into the nucleation and growth processes. Hence, an in-depth understanding about the 2D heterostructures growth processes considering different synthesis factors, is extremely important for the targeted applications. Herein, I propose nucleation and transport modeling based on atomic scale molecular dynamics simulations techniques to optimize CVD growth conditions on various effective substrates. In this project, I propose to use classical reactive MD simulations (ReaxFF) to study the growth process together with AIMD and KMC modeling for the thermodynamics energy barrier calculation and diffusion process. A supervised ML algorithm will be applied to optimize growth parameters using the trained ML model.

Teaching Statement:

Teaching Philosophy and Mentorship: Teaching and mentorship are vital to the practice of research and have created a significant impact on my scientific education and my motivation to work in academia. I strongly favor teaching core techniques and ideas above memorizing of facts and formulas. I believe that the key part of effective teaching is to take occasional breaks from lecturing to get students to refocus and to discuss conceptual questions. This method provides instant feedback on the students’ comprehension. My teaching experience has led me to the conclusion that a well-organized, interesting lecture needs to have the following elements: i) create a friendly environment in the classroom; ii) start the lecture with basic topic; (iii) convey a clear statement of the lecture's main topic; iv) numerous examples used to illustrate the main points (hands on); and v) a repetition of the take-home message at the end of the lecture.

Teaching experience: I started teaching when I was undergraduate student. At that time, I taught basic science and mathematics to several high school students. During my masters, I was appointed as teaching assistant of electrochemistry and corrosion courses. I was in-charge of few undergraduate students to demonstrate corrosion and electrodeposition at the research laboratory. I always enjoyed interacting with junior students and it helped me to have clear understanding about the basic principles of electrochemistry. During my Ph.D. period, I was teaching assistant for couple of core chemical engineering courses such as Separation Processes (CENG 3210) and Nanomaterials Application in Chemical Engineering (CENG 5840), Electrochemical Energy Technologies at Chemical and Biological Engineering department in HKUST, Hong Kong. Additionally, I mentored few undergraduate students, five M.Sc./M.Phil and three graduate students, especially students from under-represented backgrounds. At Stanford, I have participated in the teaching and mentoring workshop, graduate course design workshop, which helped me refine my methods of creating learning objectives, judging students fairly, and creating a welcoming classroom environment.

Teaching Interests: I have received my undergraduate and postgraduate degree in Applied Chemistry and Chemical Engineering, while Ph.D. in Chemical and Biological Engineering. During postgraduation, I was doing research related to metallic corrosion and electrodeposition experiments. While in my Ph.D., I have worked on solving fundamental problems associated to electrochemistry using computational simulations. My diverse (experiment and theory) educational background allows me to develop expertise in different major areas such as Chemical Engineering, Electrochemistry, Corrosion, Classical or Statistical Mechanics, Electrocatalysis, Material Science and Chemistry. During my Ph.D. and now at Stanford, I became an expert in catalysis and surface science and also in more specialized chemical engineering curriculum (kinetics, thermodynamics, transport). Overall, I feel qualified to teach general level undergraduate and graduate courses at the departments of material science, chemistry, and chemical engineering and to participate in a campus-wide, interdisciplinary science programs. In an ideal situation, I would create new course on the subject of "Heterogeneous catalysis and chemical bonding on surfaces" or a specialized course on “Computational methods for electronic structure of materials”.

In summary, my teaching philosophy is based on interactive, effective, and feedback-based approach. My research mentorship involves identifying obstacles and objectives as well as visual outcomes interpretation. My teaching interests are multidisciplinary with themes that span from material science to chemistry and chemical engineering with the scope covering both experimental and theoretical methods.