厦门大学孙毅飞团队报道了高温电催化中脱溶异质边界的定量揭示。相关研究成果于2024年11月27日发表在《美国化学会杂志》。

钙钛矿氧化物在高温电催化中的应用受到其有限活性的阻碍。脱溶是一种智能策略，可以使钙钛矿表面富集高反应性相，产生异质界面。然而，这种复杂结构的确切催化作用仍然难以确定。

该文中，研究人员对一系列钙钛矿薄膜平台（La_0.4Ca_0.4Ti_0.94Ni_0.06O₃，LCTN）的CO₂电还原反应性进行了定量分析，这些平台由出溶的异相纳米粒子（特别是Ni和NiO）增强。

交叉尺度电化学表征以及密度泛函理论（DFT）建模表明，NP/钙钛矿界面的边界长度与CO₂RR活性密切相关。在800°C下，NiO/LCTN边界处每个活性位点的固有反应速率最高为7.05±0.75×10⁴ s^-1，分别比Ni/LCTN和LCTN好2.5倍和4个数量级。

从头计算分子动力学（AIMD）证明，NiO/LCTN边界处的CO₂吸收利用了具有降低离解能垒的双齿碳酸盐形态。此外，证实了氧交换率的多重增强，这与相邻TiO₆八面体之间促进的氧离子跳跃有关。

在模型电解槽上进行的CO₂电解过程中，进一步的近环境压力X射线光电子能谱（NAP-XPS）揭示了，NiO/LCTN边界在稳定氧化碳中间体、提高不定碳的起始电位阈值以及防止其积聚方面的关键作用。

附：英文原文

Title: Quantitative Unraveling of Exsolved Heteroboundaries for High-Temperature Electrocatalysis

Author: Xiaoxin Zhang, Xiao Xiao, Qiuyue Zhang, Zhou Chen, Chang Jiang, Mingshu Chen, Ning Yan, Shidi Mo, Meng Wu, Jianhui Li, Jijie Huang, Abdullah N. Alodhayb, Xianzhu Fu, Min Chen, Xinchun Lv, Yifei Sun

Issue&Volume: November 27, 2024

Abstract: 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 CO2 electroreduction reactivity of a series of perovskite thin film platforms (La0.4Ca0.4Ti0.94Ni0.06O3, 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 CO2RR 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–1 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 CO2 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 TiO6 octahedrons. Further near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) during CO2 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.

DOI: 10.1021/jacs.4c11274

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c11274