Multi-scale Modelling of Electrochemically Promoted Systems

The objective of this work is the formulation of a multi-scale framework for electrochemically promoted systems. We have constructed a 3-Dimensional, isothermal, solid oxide single pellet, multi-scale framework, which describes the chemical and electrochemical phenomena taking place in a solid oxide single pellet under closed-circuit conditions, while the electrochemically promoted oxidation of CO over Pt/YSZ is used as an illustrative system. The proposed framework combines a 3-D macroscopic model which employs the finite element method (FEM) for the simulation of the charge transport and the electrochemical phenomena taking place in the pellet, and an in-house developed efficient implementation of a 2-D lattice kinetic Monte Carlo method (kMC) for the simulation of the reaction-diffusion micro-processes taking place on the catalytic surface. Comparison between the multi-scale framework and a macroscopic model [1] is carried out for several sets of operating conditions. Differences between the steady-state outputs of the two models are presented and discussed. A subsequent parametric study using the multi-scale framework is performed to investigate the effect of the gaseous species partial pressures and of the temperature on the CO2 production rate.