Microkinetic modeling of CO2 reduction on Pt in a solid oxide electrolysis cell

Electrolysis in solid oxide electrolysis cells is gaining significant attention as a possible pathway for CO(2 )reduction and abatement. The main objective of this work is to demonstrate the potential of microkinetic models to represent the catalytic chemistry at the cathode (negative electrode in electrolysis) and its capability to predict the cell performance. An electrochemical model in terms of the CO, CO2 and vacant site surface coverages is developed for the reduction of CO2 on Pt/YSZ electrodes. The electrochemical model is coupled to a microkinetic model through the surface coverage terms and incorporated into a one-dimensional button cell model, which resolves the cell across its thickness. The model is then used to simulate experimentally measured iV characteristics, polarization losses and electrochemical efficiency. The discussion in the paper covers aspects of parameter fitting, uniqueness, possible reasons for the differences from the experimental results, and the sensitivity of model predictions to model parameters. It also presents features of cell operation which cannot be accessed using experimental techniques. (C) 2021 Elsevier Ltd. All rights reserved.