Fully integrated, finite-volume-based, time-dependent multi-scale modeling of electrochemical CO2 reduction

초록

Electrochemical systems couple reaction kinetics and mass transport across multiple temporal and spatial scales. To address this multiscale coupling, we present an integrated Julia-based simulation framework for defining and solving complex kinetic-transport models. Specifically, CatmapInterface.jl enables the construction of mean-field reaction networks with adsorbate-adsorbate interactions and electric double layer charging-corrected electrochemical kinetics, while LiquidElectrolytes.jl enables detailed electric double layer and mass-transport models. The resulting equations are solved monolithically using the finite-volume package VoronoiFVM.jl, yielding mass-conservative and numerically robust solutions under strong transport-kinetics coupling. As an example, we study CO2 reduction on gold, for which steady-state simulations show consistent results with a previous finite-element-based implementation but improved numerical stability. Time-dependent cyclic-voltammetry simulations further provide an explanation for the experimentally observed double peak in CO re-oxidation during the anodic sweep as arising from hydroxide depletion and delayed buffer equilibration. The framework thus provides a powerful tool for nonequilibrium multiscale simulations of complex electrochemical systems.

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