Examining operando generated Ni-based alloy nanomaterials as fuel electrodes in solid oxide cells

Abstract

Constructing nanostructure through exsolution has been demonstrated as an effective approach to producing electrode materials with superior performance and stability in the application of solid oxide cells (SOCs), primarily due to the excellent catalytic properties and the significantly enhanced stability offered by the well-embedded nanoparticles that are exsolved from a supporting oxide. Here, we focus on investigating the titanate perovskites with exsolved Ni-Co alloy nanocatalysts as fuel electrodes for SOCs, particularly on operando generating these nanomaterials by applying a potential bias in CO2 electrolysis operating conditions. Three compositions of titanate perovskite were examined, La0.43Ca0.37Ti0.94Ni0.06O3−δ (LCT-Ni6), La0.43Ca0.37Ti0.94Ni0.03Co0.03O3−δ (LCT-Ni3Co3), and La0.43Ca0.37Ti0.90Ni0.05Co0.05O3−δ (LCT-Ni5Co5). Various techniques, including X-ray diffraction, thermogravimetric analysis, and DC conductivity measurement, were applied to study the crystal structure, reduction behavior, conductivity property, and microstructure of these materials. SOCs with these titanate fuel electrodes were fabricated and evaluated, with emphasis placed on operando generation of active nanomaterials through electrochemical switching in pure CO2 atmosphere, and on understanding the materials properties linking to their microstructure and performance toward CO2 electrolysis and H2 fuel cell.