Exsolution of La0.3Sr0.7Ti0.9Co0.1O3-x cathode for CO2 and H2O co-electrolysis using solid oxide electrolysis cell

Abstract

One way to achieve carbon neutrality and sustainable future energy scenarios is through the valorization of CO2 into valuable chemicals using solid oxide electrolysis cells (SOECs). However, the electrochemical performance and sulfur tolerance of cathode materials used for SOECs under a gas feed containing H2S species still requires further development. In this study, we successfully synthesized in-situ exsolved Co nanoparticles decorated on the La0.3Sr0.7Ti0.9Co0.1O3-x (LSTC) perovskite oxide (ex-LSTC) under a reductive atmosphere at high temperatures. The electrolyte-supported single cell with the ex-LSTC cathode exhibited remarkable electrocatalytic activity toward CO2 and H2O co-electrolysis with a maximum current density of approximately 705 mA/cm² and a low ASR of approximately 0.42 Ω/cm2 at 900 °C and 1.1 V. The in-situ exsolved Co nanoparticles anchored onto the LSTC backbone demonstrated excellent stability when exposed to a CO2 and H2O gas feed containing 25 ppm H2S species over an operational duration of 100 hours. Additionally, the microstructural morphology of the ex-LSTC cathode remained unchanged. Furthermore, the formation of trace amounts of sulfur impurities was negligible after treating with the H2S-containing feed, indicating highly improved sulfur tolerance and performance, which can be attributed to a larger number of exsolved Co nanoparticles and oxygen vacancies that facilitate sulfur poisoning mitigation. The findings of this study demonstrate that the in-situ exsolved LSTC can serve as a promising high-performance and sulfur-tolerant material for practical applications, particularly under direct H2S-containing flue gas streams emitted from industrial facilities.

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Identifiers

DOI

10.58837/chula.the.2022.1209

Journal

Unknown journal

Year

2022