Spinel-based oxide cathode used for high temperature CO2/H2O co-electrolysis

• Published in: Solid state ionics Vol. 329; pp. 46 - 51
• Main Authors: Wu, Kuan-Ting, Ishihara, Tatsumi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2019
• Subjects: CO2/H2O co-electrolysis; SOEC; Spinel oxide; Steam electrolysis; Water gas shift reaction; CO2/H2O co-electrolysis; Water gas shift reaction; SOEC; Steam electrolysis; Spinel oxide
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2018.11.008

Spinel oxides are applied as cathodes (fuel electrode) for the high temperature co-electrolysis of CO2/H2O mixtures. The spinel oxide is composed of two transition metals, which may improve activity for the reduction of CO2 and H2O. A series of spinel oxides have been synthesized and tested in co-electrolysis mode. A good candidate, CuFe2O4, was found and achieved a current density higher than 1 A/cm2 in CO2/H2O co-electrolysis with a fuel composition of 30%CO2/30%H2O-Ar at 800 °C, although the product was enriched in H2. This material presents superior Coulombic (Faradaic) efficiency for CO + H2 gas products, reaching more than 95%. It shows stable and reversible I-V curves, indicating good electrochemical cell performance in the co-electrolysis operation. In addition, a uniform porous structure with fine particles was observed after co-electrolysis, which may be associated with the stable and reversible electrochemical cell performance observed. •Spinel oxides applied as cathodes in high temperature co-electrolyser•CuFe2O4 performs reversible I-V curves with stable CO and H2 production.•CuFe2O4 cell presents superior Coulombic (Faradaic) efficiency.•Significant microstructural modification after co-electrolysis