(3be) Electro-Molecular Engineering of CO2 for a Circular Carbon Economy

The world is rapidly electrifying with increasingly abundant and inexpensive electrons originating from wind and solar power. Global industries, from transportation to chemical production, that traditionally rely upon fossil fuel-powered heat and pressure can be reimagined with the incorporation of electrified parts and processes. Electrification from solar and wind can power the CO₂ recycling chemistry that is a vital part of a circular carbon economy, where CO₂ from expended fuel is used to create more fuel and goods instead of accumulating in the atmosphere. The key to achieving sustainable carbon use is controlling the electro-molecular transformations during CO₂ conversion, and electrocatalysts are the tools that enable such molecular control. My research aims to optimize electrocatalyst performance by understanding chemical transformation phenomena under reaction conditions with specialized measurement techniques.

Electrochemical processes occur at the solid-electrolyte interface, so it is necessary for experimental measurements to probe the near-surface environment under reaction conditions. During my post-doctoral studies at the National Institute of Standards and Technology, I am developing these techniques for electrochemical CO₂reduction to understand concentration gradients, real-time product formation, and molecular orientations near the electrode.¹ As one example, I directly measure the reaction-induced pH gradient in the boundary layer, which impacts the CO₂ reaction mechanism. This gradient can be described by a convection-diffusion model, and it is influenced by the electrolyte composition, electrode kinetics, and applied potential. These measurements will guide development of electrocatalysts that optimize pH gradients to favor desired CO₂ product pathways. The technique is also applicable to research opportunities in many other aqueous electrochemical processes that either produce or consume protons.

It is also necessary to understand the chemical state of the electrocatalyst itself under reaction conditions. Synchrotron X-ray techniques are capable of measuring catalyst properties within a device while it is operating. During my thesis studies under Prof. Jingguang Chen at Columbia University, we used synchrotron techniques to draw correlations between the chemical state of the active site and catalyst selectivity to optimize electrochemical syngas production on palladium-based electrocatalysts.² I will apply a similar approach to rational design of electrocatalysts for other CO₂ electroreduction products, especially where copper electrode surfaces are known to change rapidly and impact product selectivity.

Boundary layer phenomena and active site control are fundamental aspects of any electrocatalytic process, so the tools described here can be extended to electrocatalyst development for increasingly complex and specific commodity chemicals. Selection of which reactions to pursue will be guided by global sustainability goals and chemical engineering analysis of potential processes, similar to my work in a recent Perspective article on methanol production from CO₂.³ My poster will present more details about how I use my measurement expertise to develop electrocatalysts that control molecular CO₂ transformations that will enable a sustainable and circular carbon economy.

References:

1. B. M. Tackett and T. P. Moffat, ECS Meet. Abstr., 2020, MA2020-01, 1754–1754.
2. B. M. Tackett, J. H. Lee and J. G. Chen, Acc. Chem. Res., 2020, Accepted.
3. B. M. Tackett, E. Gomez and J. G. Chen, Nat. Catal., 2019, 2, 381–386.

Teaching Interests:

As a chemical engineering instructor, I strive to provide students with the skills that reflect the industrial landscape into which they will be hired. Automotive, energy, and chemical industries are increasing efforts in their battery and fuel-cell divisions, and they require engineers with basic electrochemical toolsets. Luckily, the fundamentals of electrochemistry can be built directly on the chemical engineering foundation of mass and energy balances, thermodynamics, transport, and kinetics. I will supplement traditional treatments of these subjects with analogous electrochemical formulations to give students a working knowledge of the processes that will increasingly be driven by electrons. For students who desire more in-depth study of electrochemical processes, I can offer a specialized electrochemical engineering course with a focus on surface phenomena, which is closely aligned to my research efforts.

I am committed to incorporating research-based pedagogical methods into course structures to maximize learning outcomes for all students. During my graduate studies I completed the Teaching Development Program through the Columbia Center for Teaching and Learning, where I studied techniques like backward design and active learning to develop a student-centered approach to teaching. This framework creates the opportunity to explicitly include activities and lessons that engage diverse ideas and perspectives, so that all students have an equal opportunity for success. These methods not only benefit students, but they also streamline the instructor’s role by generating channels for feedback that can guide planning and assessments.