(3cm) Understanding Electrochemical Interfaces for Sustainable Energy Conversion and Storage

The central focus of my research is to advance experimental and computational methods to develop highly efficient electrochemical systems for clean energy production & storage and understanding the dynamics at the electrode-electrolyte interface to gain fundamental mechanistic insight into sustainable electrochemical reactions. By using ubiquitous synthons- CO₂, CH₄, N₂, and H₂O- this research aims to build a fundamental understanding of the conversion of CO₂ to hydrocarbons, CH₄ to methanol, N₂ to NH₃, and using H₂O in combination with the other synthons to produce oxygenated fuels or fertilizer products.

Background and Motivation:

Electrochemical routes are a sustainable alternative to the combustion of fossil fuels for energy production and storage. Electrochemical conversion is particularly attractive because of its high reaction rate, high control over the product selectivity, relatively milder operating conditions, and a great potential for large-scale industrial applications. Electrochemical reduction of CO₂ is an appealing synthesis step as it treats the CO₂ not as a global warming liability but as a raw material to produce hydrocarbons that can be used as fuels for energy consumption or to produce CO which is an important industrial precursor. Electrochemical oxidation of CH₄ is a topic of significant interest as well as it presents a means for oxidizing CH₄ leading to a prospect of methanol economy providing economical and environmentally sustainable means to store energy as a direct CH₄/ CH₃OH fuel cell or by converting CH₄ to value-added hydrocarbons. Developing ambient temperature-pressure routes for electrochemical ammonia synthesis from N₂ is of exceptional scientific, societal, and industrial importance as it aims to circumvent the conventional extremely high energy-intensive Haber-Bosch process. Electrochemically synthesized NH₃ may also be used in further downstream chemical processes which is an alternate and safer route to store electrical energy in chemical energy compared to the current standard H₂ as a cleaner fuel. In tandem with the C-H and N-N electrochemical activation, introducing H₂O as a source of oxygen is an innovative route to produce oxygenated fuels or fertilizer products. This not only offers a sustainable synthesis but also circumvents the use of flammable O₂ in such a process.

Electrochemical processes are far from replacing conventional industrial processes as they are still not as efficient. One of the primary reasons for this is that we know very little about what happens on a molecular level- the interaction between the catalyst site, reactant molecule, and the electrolyte. Hence, for a knowledge-based development of electrochemical processes, it is important to obtain a fundamental insight into the electrode-electrolyte interface. Understanding this interface is a challenging task as even simplest of the electrochemical systems may have a multicomponent/multiphase bulk electrolyte which is even more complex at the electrode-electrolyte interface which is an intersection of at least three phases: electrode (solid), electrolyte (liquid), and reactant molecule (gas/adsorbed species). Furthermore, there is an active potential gradient across this interface which gives rise to strong electric fields in the vicinity of the capacitive double layer. Therefore, this research aims at getting a fundamental understanding of the dynamics of the electrochemical interface both experimentally and computationally.

Research Area 1: From Synthesis of Electrocatalysts to Probing the Interface

This research area aims to synthesize isolated clusters of transition metal atoms on graphene using chemical vapor deposition (CVD) as graphene’s 2D structure and high electronic properties make it an excellent support for metal atom distribution on a large surface area thereby reducing the size of the electrocatalyst and increasing its activity by keeping the metal atoms in an undercoordinated environment in an aqueous electrolyte for C-H or N-N electrochemical activation. The synthesis of single-atom catalysts can be optimized by changing the metal concentration or by doping the graphene support to get the highest efficiency of the desired product. The interface can be probed by in-situ and operando ATR-FTIR studies to understand the propagation of an electrochemical reaction by observing the adsorbed species on the electrocatalytic sites.

Research Area 2: Continuum Modeling and Machine Learning at the Interface

Continuum modeling part of this research is aimed at understanding the underlying physics at the interfaces including chemical species transport, charge transfer reactions, and fluid flow. Cyclic voltammetry (CV) is one of the techniques providing important mechanistic insight into an electrochemical reaction. Additionally, interpreting an experimental CV can be influenced by subjectivity from the experience of the electrochemist. Machine Learning (ML) algorithms can be applied in such cases to circumvent the heuristics in CV interpretations and user subjectivity to present robust, quantifiable confidence in predicting electrochemical reaction mechanisms. ML will also be applied to guide an optimized synthesis of single transition metal atom-based electrocatalysts.

The experimental and computational techniques can be used synergistically as seen in the attached figure.

Teaching Interests

As we see publications in high impact journals as an output to our research, directly influencing students and invoking curiosity in them is what I consider as a tangible output from teaching -both equally important skills in academia. I’ve had the experience of teaching graduate and undergraduate students from very diverse backgrounds over 7 years as a TA in two different universities with courses like Chemical Engineering Thermodynamics, Reaction Engineering, Process Calculations, Unit Operations lab, General Chemistry, and Microbiology lab. My pedagogy is to approach a course in a way that gives the students a formal training in the subject but would also be relatable to the students in their daily lives, so the learning isn’t lost on the students due to the abstractness of the coursework. Teaching must be adapted to the learning style of students. In my experience, two strategies are effective to keep the students engaged in course i) by showing the chemical engineering in the things they interact with regularly. ii) by assigning an open-ended project to use the fundamentals learned in the course to apply in their area of research (especially for graduate students). Chemical Engineering is a constantly evolving field and now along with the formal training in core courses, I believe elective courses can also be introduced in a school’s curriculum to prepare the students for the ventures in industry or academia. My rigorous training in core chemical engineering subjects has made me confident in teaching a core course on “Chemical Reaction Engineering” and my current research interests have led to propose two elective courses. The first course will be “Fundamentals of Electrochemistry” which will begin from the basic electrochemistry from general chemistry and will gradually advance to understanding the Nernst-Planck equation, double-layer capacitance, and experimental electrochemical techniques. The second course will be inclined towards data science on “Machine Learning Applications in Chemical Engineering”. Here, the students will learn to build simple linear regression algorithms and move to train complex artificial neural networks. Students will learn how the industry is using data science to optimize their high-throughput manufacturing process and in the end, they will apply machine learning principles to their research. I believe my teaching capabilities will add diversity to the existing teaching program and will help in preparing better chemical engineers in the future.