ChE PhD Dissertation Defense: Erin Heeschen

Name:
Erin Heeschen

Title:
Temporal and Spatial Control of Structure and Rheology in Binary Colloidal Gels

Date:
08/18/2026

Time:
10:00:00 AM

Committee Members:
Prof. Magda Barecka (Advisor)
Prof. Marion Börnhorst
Prof. Damilola Daramola
Prof. Richard West

Location:
Behrakis Health Sciences Center 424

Abstract:
Chemical production plants contribute to a significant portion of global carbon emissions, making them a key target for decarbonization efforts. Carbon dioxide (CO₂) electrolysis is a promising pathway towards decarbonization that utilizes renewable energy to convert emitted CO₂ into valueadded chemicals. While the environmental and industrial incentives to support this technology are apparent, further progress toward large-scale implementation remains constrained by inconsistent performance.

Electrolyte flow within CO₂ electrolyzers influences crucial parameters such as local velocity and pressure, interfacial pH gradients, and gas bubble accumulation, which can be controlled through flow-field design. Neighboring fields of electrochemistry, including fuel cells, redox flow batteries, and water electrolyzers, have identified uniform catholyte flow as a vital parameter to enhance electrochemical stability and energy efficiency. Despite the importance of catholyte flow fields, flow field geometries are rarely reported in the CO₂ electrolysis literature, and it is unknown how uniform catholyte flow influences cell performance.

The hypothesis investigated in this dissertation is that understanding the relationship between catholyte flow uniformity, reproducibility, and the electrochemical performance of CO₂ electrolyzers can allow us to design flow fields that allow for better flow control, better selectivity, and more predictable outcomes of electrochemical reactions. To address this hypothesis, this dissertation includes a workflow to design, simulate, 3D print, validate, and experimentally test four catholyte flow field geometries for use in flow-based CO₂ electrolyzers. Liquid flow is simulated through each catholyte flow field at four inlet flow rates using ANSYS Fluent to analyze electrolyte uniformity distribution and pseudo-boundary layer thicknesses. Each design was 3D printed and the simulations validated using a novel instance segmentation program for use in volumetrically small cells. Finally, two of the investigated catholyte flow field geometries are deployed in a liquid-liquid CO₂ electrolyzer. Results indicate that uniform catholyte distribution strongly enhances experimental reproducibility. However, it is challenging to achieve the highest single-product selectivity without losing flow uniformity. Based on these findings, general design rules are established to support the further development of electrolyzers amenable to scale-up and industrial application.

Erin Heeschen is a 4th year Chemical Engineering PhD Candidate in the College of Engineering at Northeastern University dedicated to sustainability focused technologies. In August 2026, she will be defending her doctoral thesis in the field of Chemical Engineering with a specialization in CO2 electrolysis and reactor design. Erin was nominated to Sigma Xi, the Scientific Research Honor Society, and is an active member of the New England section of the Electrochemical Society. In addition to recognized excellence in research, Erin is an established science communicator for cutting edge research in field of sustainability and electrochemistry. She designed and headed a booth for the Barecka Lab’s Airthanol project at the 2026 ARPA-E Energy Summit in San Diego, CA (winning honorable mention for best booth) and 2026 Sustainability Innovation Week Expo at Northeastern University; she placed 2nd in the Graduate Student Research Presentations at the Northeastern University Poster Showcase Presentation Competition (2023) and was nominated best elevator pitch by her cohort (2023); she also presented her research at numerous conferences such as MRS (Material Research Society), ACS-GCI (American Chemical Society Green Chemistry Institute) Pharmaceutical Roundtable, and AIChE (American Institute for Chemical Engineers) in Boston. Outside of her research, Erin is a longtime boardgame enthusiast (even going so far as to open a board game store when she was 17!) who will never turn down a long hike through the woods.