Vanessa Jane Bukas

During the EIRES Energizing Day on Friday June 23^rd, renowned speakers from within and outside of TU/e presented the latest in energy-related research. Theorist Vanessa Jane Bukas from the Fritz-Haber-Institut der Max-Planck-Gesellschaft in Berlin talked about her work on modelling reaction mechanisms in electrocatalysis.

Vanessa Jane Bukas studied Applied Mathematics & Physics at the National Technical University of Athens, obtained a Master’s degree in Materials Science from the Ludwig-Maximilians Universität München, and holds a PhD in Theoretical Chemistry from the Technical University Munich. Since February 2021, she has been leading a research group of the Theory Department at the Fritz-Haber-Institut der Max-Planck-Gesellschaft.

Bukas works on gaining a fundamental understanding of heterogeneous thermal and electro-catalytic processes, with a special focus on product selectivity. Her talk at the EIRES Energizing Day will focus on the electrocatalysis part of her work. ‘To me, science is about solving problems,’ Bukas states. ‘Catalysis is an interesting topic, because of its complexity and of its clear societal relevance. The thing with electrocatalysis is that the underlying mechanisms are still rather poorly understood. In my group, we focus on modelling the electrochemical interface to understand the chemical reactions that occur. That is a challenging task, since we have to consider many different scales in terms of length and time, and many different processes.’

Different scales
The Bukas group integrates electronic structure calculations with thermodynamic and kinetic modeling, with the aim to provide predictive-quality simulations of atomic-scale resolution. ‘We look at elementary reaction steps, for example how charge transfer changes the catalytic efficiency or how the mesoscopic morphology of the electrode influences the reaction path that is being followed and hence the product that is being formed. One important question we always ask ourselves is what the required level of theory is. If we were to model the entire system on a quantum mechanical level, the resulting problem is way too big to compute.’

In her projects, Bukas typically focusses on one of the half-reactions in an electrochemical device, so she looks at either the anode or the cathode. ‘We try to describe what happens at the electrode including as much of the environment as we can. So, we take into account the material properties of the active catalyst surface, the dynamics of the solvent, the role of ions, the morphology of the electrode, and so on. Based on our models we make a prediction of which reactions will occur, and what will be the rate limiting steps.’ That is valuable information for the engineers who try to upscale reactors and improve their efficiency, stability and selectivity, since it provides them with clues on how to design the catalysts, pick the best materials, or optimize the cell layout.

Selectivity and degradation
At the EIRES event, Bukas will be presenting two different projects. ‘Current thermodynamic models often fail to describe the selectivity of technologically important electrocatalytic reactions. I will address some alternative scenarios as to why this may be.’ The first is on the effect of the applied electrode potential. The second project is about also accounting for mesoscopic mass transport and dynamic morphology changes that can also play a big role in catalyst ageing or degradation.’

Bukas is driven by the notion that she is working towards large scale implementation of a technology that will aid the energy transition. ‘My role is to provide a fundamental understanding of reaction principles. Though complex, I see that as a fun and rewarding challenge. I am an optimist, and I am convinced that if we get together and put our minds to something, we can achieve great things.’