Collectively, this work reveals the immense importance of invoking a true multi-scale picture of catalysis when modeling, because mesoscale mass transfer, nanoscale double layer structure, and molecular energetics all interplay non-intuitively and have critical effects that dictate observed rates!

Finally, we extend the model to explore how it can explain enhancements in CO2R observed upon the use of an inert salt that suppresses dielectric constant. This is a first step into understanding the role of non-standard solvent environments in CO2R and their effects on catalysis.

This shows that the terms that we so-often like to neglect as chemical engineers become really important in the concentrated environment of the electrical double layer, which is the environment in which electrocatalysis occurs!

Sensitivity analysis on the model reveals the importance of the solvent permittivity, the role of mass transfer, and the importance of each of the non-ideal terms in the excess chemical potential in enabling accurate prediction of rates.

The reduced reorganization energy increases the rate of CO2R as predicted by a Marcus-Hush-Chidsey framework for electron-transfer-limited coupled-ion-electron-transfer employed in our continuum model.

This allows us to really get to the heart of how the double layer structure controls rates in CO2R. Smaller hydrated cations pack more tightly in the EDL, which increases local electric fields, lowering dielectric permittivity, and correspondingly reducing the solvent reorganization energy.

The model employs zero adjustable parameters, and faithfully and quantitatively predicts the rate of CO2RR as a function of cation, electrolyte strength, and CO2 activity, as well as the local pH and CO2 activity measured by ATR-SEIRAS!

We also find that having an accurate double layer structure in the simulation allows us to get very accurate predictions of catalytic rates in our continuum model.

In this work, we develop a multi-scale model of the electrical double layer in CO2 reduction. By including a variety of non-ideal ion-specific effects, such as cation hydrolysis, steric excess potentials, and more, we can accurately the structure of the double layer as confirmed by impedance.

Thank you Nathan!!

Thank you Jordi!!

Thank you Kelsey!!

Link to the original study here: www.nature.com/articles/s44...

Thanks!!

Finally, thanks to @ucberkeleyofficial.bsky.social and @berkeleylab.bsky.social for being such a great home to work on BPM research for the last 5 years. Super proud of all that we were able to do together on this topic, and looking forward to watching this space in the future! (11/11)

I also want to give a special shoutout to my former undergraduate mentee, Andrew Liu who performed many of the initial simulations that provided the groundwork for the findings in this work. (10/11)

This work was a massive team effort and could not have been done without my exceptional collaborators, Eric Lees, James Toh, Nathan Stovall, Priyamvada Goyal, and Kiko Galang, along with the support of our PIs, Adam Weber, Alexis Bell, and Yogi Surendranath. (9/11)

Finally, we highlight potential routes to alleviate these challenges, identifying that rational materials design of BPMs with high concentrations of selective fixed-charge will be pivotal to enabling these future technologies! (8/11)

For this reason, CO2 absorption into the AEL as carbonates is an existential challenge for FB-BPMs, because divalent carbonate anions thoroughly outcompete OH- for recombination sites at the interface. (7/11)