Abstract
We present a multiscale approach that couples ab initio microkinetic simulations and two-dimensional (2D) continuum transport models to study electrochemical reduction to on electrodes in a flow reactor configuration. We find the key parameters, including concentration, , the current density towards , and the Tafel slopes, to strongly depend on the applied potential and position on the electrode. We find a rapid decrease in the concentration and current density towards as a function of electrode position. We further discuss two strategies to improve availability: increasing the shear or flow rate of and the introduction of a defect in between the electrode. In both cases, increased availability results in increased current density at the higher potentials. We find good agreement between a 1D continuum transport model with an effective boundary layer thickness corresponding to the shear rate used for the 2D simulations. Finally, we provide a phenomenological model that can be used instead of the microkinetic model to accelerate the multiscale simulations when extended to higher dimensions and more complicated reactor geometries.
- Received 19 May 2023
- Revised 3 July 2023
- Accepted 24 July 2023
DOI:https://doi.org/10.1103/PRXEnergy.2.033010
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
The global increase in anthropogenic carbon emissions and the looming climate crisis necessitate the accelerated deployment of carbon-neutral technologies in the near future. Electrochemical reduction to high-value fuels and chemicals using renewable electricity is a promising solution. Resolving the reaction environment in the vicinity of the electrode during reduction is crucial to obtain accurate mechanistic insights and improve reactor performance. Here, the authors present a multiscale modeling approach that couples ab initio microkinetic simulations with a two-dimensional continuum transport model of a flow reactor to resolve the reaction environment during electrochemical reduction on Au electrodes. They find that faster flow rate and the introduction of an inert area on the electrode improve the utilization.
