Microstructure of hydrogen electrode catalyst layer materials for solid oxide electrolysis cells

Abstract

This research explores the synthesis of Ce0·6Mn0·3Fe0·1O2-δ (CMF) catalyst using the citric acid-EDTA method. CMF mixtures with various active carbon pore-forming amounts are achieved through controlled atmosphere sintering, revealing low permeability and high porosity. The permeability correlates with the microstructure. Results show poor porosity in unsintered carbon at 1250 °C. Increasing the amount of pore-forming powders does not enhance porosity. Sintering CMF and 9% active carbon at 1250 °C under Ar and then in air at 900 °C increases active carbon porosity, resulting in a mixture with a specific surface area of 2.11 m2 g−1 and porosity of 50.82%. This composition surpasses others in characteristics. Electrochemical assessment of solid oxide electrolysis cells (SOECs) indicates that Pt/SDC/CMF+9%AC (cell B) outperforms Pt/SDC/Pt (cell A), demonstrating potential for CMF oxide cathodes in steam electrolysis during SOEC operations with a current density of 847 mA cm−2 at 1.5 V.