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Quantitative Unraveling of Exsolved Heteroboundaries for High-Temperature Electrocatalysis
The application of perovskite oxide for high-temperature electrocatalysis is hindered by its limited activity. Exsolution is a smart strategy that allows the enrichment of the perovskite's surface with highly reactive phases, yielding heteroboundaries. However, the identification of the exact c...
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Published in: | Journal of the American Chemical Society 2024-11 |
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Main Authors: | , , , , , , , , , , , , , , , |
Format: | Article |
Language: | English |
Online Access: | Get full text |
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Summary: | The application of perovskite oxide for high-temperature electrocatalysis is hindered by its limited activity. Exsolution is a smart strategy that allows the enrichment of the perovskite's surface with highly reactive phases, yielding heteroboundaries. However, the identification of the exact catalytic role of this complex architecture is still elusive. Here we presented a quantitative analysis of the CO
electroreduction reactivity of a series of perovskite thin film platforms (La
Ca
Ti
Ni
O
, LCTN) boosted by exsolved heteropical nanoparticles (particularly for Ni and NiO). The cross-scale electrochemical characterizations, together with density functional theory (DFT) modelings, have shown clear evidence that the boundary length of the NP/perovskite interface is strictly correlated with the CO
RR activity. The intrinsic reaction rate per active site at the NiO/LCTN boundary demonstrates a highest turnover frequency (TOF) of 7.05 ± 0.75 × 104 s
at 800 °C, which is 2.5 times and 4 orders of magnitude better than that of Ni/LCTN and LCTN, respectively. The ab initio molecular dynamics (AIMD) proves that the CO
absorption at the NiO/LCTN boundary leverages a bidentate carbonate modality with a reduced dissociation energy barrier. Moreover, a multifold enhancement in oxygen exchange rate was confirmed, which correlated to the facilitated oxygen ion hopping between adjacent TiO
octahedrons. Further near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) during CO
electrolysis on model electrolyzers reveals the crucial role of the NiO/LCTN boundary in stabilizing oxidized carbon intermediates, raising the onset potential threshold of adventitious carbon as well as preventing its build-up. |
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ISSN: | 1520-5126 1520-5126 |
DOI: | 10.1021/jacs.4c11274 |