Elementary kinetic modeling and experimental validation of electrochemical CO oxidation on Ni/YSZ pattern anodes

摘要

Carbon monoxide (CO) is a major component in typical feed gases for solid oxide fuel cells (SOFC). This paper presents a combined modeling and experimental analysis of electrochemical CO oxidation on Ni/YSZ patterned model anodes. A computational model representing the coupled behavior of heterogeneous chemistry and electrochemistry in terms of elementary reactions is developed, which allows for a quantitative description of electrochemical impedance spectra and current-voltage behavior. Excellent agreement between model and experiment was achieved for the complete experimental data set, which covers a wide range of CO/Co_2/N_2 gas compositions (4.0 × 10~2 Pa ≤ pCO ≤ 5.1 × 10~4 Pa and 9.5 × 10~2 Pa ≤ pCO_2 ≤ 9.2 × 10~4 Pa) and operating temperatures (973 K ≤ T ≤ 1073 K). In the framework of the presented model a direct mechanistic interpretation of the experimentally observed electrochemical characteristics is obtained.