Understanding the Roles of Double- and Triple-Phase Boundaries in High-Temperature CO<sub>2</sub> Electrolysis.
basic_science · Level V
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- Record sourced from PubMed, PMID 41159816.
- Also identified by DOI 10.1021/acs.nanolett.5c04454.
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Abstract
High-temperature solid oxide electrolysis cells are promising for CO<sub>2</sub>-to-CO conversion with high selectivity and energy efficiency. However, the correlation between the electrolysis performance and electrode interface structure remains poorly understood. Here, in a Ni/ceria system, we demonstrate that the segregation-free Ni-doped ceria forms double-phase boundaries (DPBs) with CO<sub>2</sub>, offering a CO outlet concentration of 83.0 ± 0.2%. By contrast, carbon deposition was seen in controls with triple-phase boundaries (TPBs) formed by segregated Ni and ceria interfacing with CO<sub>2</sub>. The electrochemical activity strongly correlates with oxygen vacancy (O<sub>v</sub>) concentrations in Ni/ceria. The segregation-free Ni/ceria catalyst achieves 1.4 A cm<sup>-2</sup> at 1.65 ± 0.01 V and operates stably at 600 mA cm<sup>-2</sup> for 220 h without any decay in activity. The results indicate that enriching O<sub>v</sub> at DPBs promotes high-temperature CO<sub>2</sub> electrolysis, with a more influential role than TPBs for these ceria-based catalysts.