Magkoev Tamerlan
Laboratory of Surface Physics and Catalysis, Department of Condensed Matter Physics, North Ossetian State University, Vatutina 44-46, 362025 Vladikavkaz, Russia.
Materials (Basel). 2021 Jan 20;14(3):485. doi: 10.3390/ma14030485.
Formation of gold nanosized particles supported by aluminum oxide film grown on Mo(110) substrate and oxidation of carbon monoxide molecules on their surface have been in-situ studied in ultra-high vacuum by means of Auger electron spectroscopy (AES), reflection-absorption infrared spectroscopy (RAIRS), low energy electron diffraction (LEED), atomic force microscopy (AFM), temperature-programmed desorption (TPD), and work function measurements. The main focus was to follow how the thickness of the alumina film influences the efficiency of CO oxidation in an attempt to find out evidence of the possible effect of electron tunneling between the metal substrate and the Au particle through the oxide interlayer. Providing the largest degree of surface identity of the studied metal/oxide system at different thicknesses of the alumina film (two, four, six, and eight monolayers), it was found that the CO oxidation efficiency, defined as CO to CO TPD peaks intensity ratio, exponentially decays with the oxide film thickness growth. Taking into account the known fact that the CO oxidation efficiency depends on the amount of excess charge acquired by Au particle, the latter suggests that electron tunneling adds efficiency to the oxidation process, although not significantly.
通过俄歇电子能谱（AES）、反射吸收红外光谱（RAIRS）、低能电子衍射（LEED）、原子力显微镜（AFM）、程序升温脱附（TPD）以及功函数测量等手段，在超高真空环境下对生长在Mo(110)衬底上的氧化铝膜负载的金纳米颗粒的形成及其表面一氧化碳分子的氧化进行了原位研究。主要关注点在于探究氧化铝膜的厚度如何影响一氧化碳氧化效率，试图找出金属衬底与金颗粒之间通过氧化物中间层进行电子隧穿可能产生的影响的证据。在氧化铝膜不同厚度（两层、四层、六层和八层）下确保所研究的金属/氧化物体系具有最大程度的表面一致性，结果发现，以一氧化碳与二氧化碳TPD峰强度比定义的一氧化碳氧化效率随氧化膜厚度的增加呈指数衰减。考虑到一氧化碳氧化效率取决于金颗粒获得的过量电荷量这一已知事实，这表明电子隧穿虽对氧化过程效率有提升作用，但并不显著。
