Li Haixia, Wang Wanhua, Wang Lucun, Wang Min, Park Ka-Young, Lee Taehee, Heyden Andreas, Ding Dong, Chen Fanglin
Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States.
Energy & Environmental Science and Technology, Idaho National Laboratory, Idaho Falls, Idaho 83401, United States.
ACS Appl Mater Interfaces. 2023 Sep 20;15(37):43732-43744. doi: 10.1021/acsami.3c08561. Epub 2023 Sep 6.
Massive carbon dioxide (CO) emission from recent human industrialization has affected the global ecosystem and raised great concern for environmental sustainability. The solid oxide electrolysis cell (SOEC) is a promising energy conversion device capable of efficiently converting CO into valuable chemicals using renewable energy sources. However, Sr-containing cathode materials face the challenge of Sr carbonation during CO electrolysis, which greatly affects the energy conversion efficiency and long-term stability. Thus, A-site Ca-doped LaCaCoFeO (0.2 ≤ ≤ 0.6) oxides are developed for direct CO conversion to carbon monoxide (CO) in an intermediate-temperature SOEC (IT-SOEC). With a polarization resistance as low as 0.18 Ω cm in pure CO atmosphere, a remarkable current density of 2.24 A cm was achieved at 1.5 V with LaCaCoFeO (LCCF64) as the cathode in LaSrGaMgO (LSGM) electrolyte (300 μm) supported electrolysis cells using LaSrCoFeO (LSCF) as the air electrode at 800 °C. Furthermore, symmetrical cells with LCCF64 as the electrodes also show promising electrolysis performance of 1.78 A cm at 1.5 V at 800 °C. In addition, stable cell performance has been achieved on direct CO electrolysis at an applied constant current of 0.5 A cm at 800 °C. The easily removable carbonate intermediate produced during direct CO electrolysis makes LCCF64 a promising regenerable cathode. The outstanding electrocatalytic performance of the LCCF64 cathode is ascribed to the highly active and stable metal/perovskite interfaces that resulted from the exsolved Co/CoFe nanoparticles and the additional oxygen vacancies originated from the CaFeO phase synergistically providing active sites for CO adsorption and electrolysis. This study offers a novel approach to design catalysts with high performance for direct CO electrolysis.
近期人类工业化过程中大量的二氧化碳（CO）排放已经影响了全球生态系统，并引发了对环境可持续性的高度关注。固体氧化物电解槽（SOEC）是一种很有前景的能量转换装置，能够利用可再生能源将CO高效地转化为有价值的化学品。然而，含Sr的阴极材料在CO电解过程中面临Sr碳酸化的挑战，这极大地影响了能量转换效率和长期稳定性。因此，开发了A位Ca掺杂的LaCaCoFeO（0.2≤ ≤0.6）氧化物，用于在中温SOEC（IT-SOEC）中将CO直接转化为一氧化碳（CO）。在800℃下，以LaSrGaMgO（LSGM）电解质（300μm）支撑的电解槽中，以LaCaCoFeO（LCCF64）为阴极、LaSrCoFeO（LSCF）为空气电极，在纯CO气氛中极化电阻低至0.18Ω·cm²，在1.5V时实现了2.24A·cm⁻²的显著电流密度。此外，以LCCF64为电极的对称电池在800℃、1.5V时也显示出1.78A·cm⁻²的有前景的电解性能。此外，在800℃下以0.5A·cm⁻²的恒定电流进行直接CO电解时，已经实现了稳定的电池性能。直接CO电解过程中产生的易于去除的碳酸盐中间体使LCCF64成为一种有前景的可再生阴极。LCCF64阴极出色的电催化性能归因于高度活性和稳定的金属/钙钛矿界面，这是由析出的Co/CoFe纳米颗粒以及源自CaFeO相的额外氧空位协同作用提供了CO吸附和电解的活性位点。这项研究为设计用于直接CO电解的高性能催化剂提供了一种新方法。
