Elucidating the NO_x purification mechanism of exhaust gas catalysts such as Rh nanoparticles is essential for the development of air purification technology required for environmentally conscious automobiles. In this study, operando observations of Rh nanoparticles in NO gas were performed to understand the Rh surface structure and dynamics. A system comprising a high-voltage electron microscope (HVEM) connected to a high-sensitivity quadrupole mass spectrometer (QMS) (HVEM-QMS system), which was newly developed by Nagoya University and JEOL, was used for gas analysis. While confirming the onset of the NO reduction reaction using the QMS, structural changes in the Rh nanoparticles in the presence of NO gas with increasing temperature were investigated. The repeated appearance and disappearance of a surface oxide film was observed for the first time, suggesting that the metastable surface oxidation state contributes to the uptake and release of oxygen during NO decomposition.

阐明 NO _xRh纳米颗粒等废气催化剂的净化机理对于开发具有环保意识的汽车所需的空气净化技术至关重要。在这项研究中，对 NO 气体中的 Rh 纳米粒子进行了操作观察，以了解 Rh 表面结构和动力学。使用由名古屋大学和 JEOL 新开发的由连接到高灵敏度四极杆质谱仪 (QMS) 的高压电子显微镜 (HVEM) 组成的系统（HVEM-QMS 系统）进行气体分析。在使用 QMS 确认 NO 还原反应开始的同时，研究了在 NO 气体存在下随着温度升高，Rh 纳米颗粒的结构变化。首次观察到表面氧化膜的反复出现和消失，