NIOBIUM and its oxides are a new kind of materials applied in technical fields, such as catalysis, microelectronics, ceramics and optical glass. In order to understand the surface structure and catalytic activity, muc...NIOBIUM and its oxides are a new kind of materials applied in technical fields, such as catalysis, microelectronics, ceramics and optical glass. In order to understand the surface structure and catalytic activity, much work has been done on the oxidation of niobium. These results indicated that the oxidation process of niobium surface, the distribution and the structure of niobium oxides on the surface are all closely related to the condition of the oxidation process. Due to the high activity of niobium and the complexity of niobium oxide species, up to now there has not been a clear picture of the structure and the forming condition of the niobium oxides. HREELS is a powerful tool to investigate vibrational and structural properties of surface, but the HREELS study of the oxidation of Nb single crystal by O<sub>2</sub> has never been reported before. In this note we investigated the oxidation of Nb（110） and the structure and adsorption properties of the oxide film using HREELS, UPS and AES.展开更多
低温(110～130K)下,将次表层Fe结构的Pt-Fe模型催化剂(即Pt/Fe/Pt(111)结构)暴露于不同量CO气体,经不同温度退火后,采用高分辨电子能量损失谱(HREELS)研究催化剂表面CO分子的振动谱。结果表明,当CO的暴露量低于0.2 L (Langmuir)时,Pt/Fe...低温(110～130K)下,将次表层Fe结构的Pt-Fe模型催化剂(即Pt/Fe/Pt(111)结构)暴露于不同量CO气体,经不同温度退火后,采用高分辨电子能量损失谱(HREELS)研究催化剂表面CO分子的振动谱。结果表明,当CO的暴露量低于0.2 L (Langmuir)时,Pt/Fe/Pt(111)表面只存在顶位吸附;当暴露量大于0.4L,除了顶位吸附外,桥位吸附开始出现;顶位吸附分子的C-O键振动峰随着暴露量的增加不断向高波数方向偏移。退火温度影响Pt/Fe/Pt(111)表面CO的吸附形式,低于255K时,顶位吸附分子的脱附速率大于桥位吸附分子;高于255 K时,桥位吸附分子的脱附速率较大,并先于顶位吸附的CO从表面完全脱附,其完全脱附温度比Pt(111)表面低50 K。展开更多
A novel instrument that integrates reflection high energy electron diffraction(RHEED),electron energy loss spectroscopy(EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and s...A novel instrument that integrates reflection high energy electron diffraction(RHEED),electron energy loss spectroscopy(EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and spatial information of the same surface region via the simultaneously acquired patterns of RHEED,EELS,and energy-filtered electron microscopy,it is named correlative reflection electron microscopy(c-REM).Our simulation demonstrates that the spatial resolution of this c-REM is lower than 50 nm,which meets the requirements for in-situ monitoring the structural and chemical evolution of surface in advanced material.展开更多
文摘NIOBIUM and its oxides are a new kind of materials applied in technical fields, such as catalysis, microelectronics, ceramics and optical glass. In order to understand the surface structure and catalytic activity, much work has been done on the oxidation of niobium. These results indicated that the oxidation process of niobium surface, the distribution and the structure of niobium oxides on the surface are all closely related to the condition of the oxidation process. Due to the high activity of niobium and the complexity of niobium oxide species, up to now there has not been a clear picture of the structure and the forming condition of the niobium oxides. HREELS is a powerful tool to investigate vibrational and structural properties of surface, but the HREELS study of the oxidation of Nb single crystal by O<sub>2</sub> has never been reported before. In this note we investigated the oxidation of Nb（110） and the structure and adsorption properties of the oxide film using HREELS, UPS and AES.
基金sponsored by the National Basic Research Program of China(973 Program)under grant no.2015CB351905the National Natural Science Foundation of China(no.61504019)+3 种基金China Postdoctoral Science Foundation(no.2015M580783)Scientific Research Start-up Foundation of University of Electronic Science and Technology of China(Y02002010301082)the Technology Innovative Research Team of Sichuan Province of China(no.2015TD0005)the Fundamental Research Funds for the Central Universities of China(no.ZYGX2015J140)
文摘低温(110～130K)下,将次表层Fe结构的Pt-Fe模型催化剂(即Pt/Fe/Pt(111)结构)暴露于不同量CO气体,经不同温度退火后,采用高分辨电子能量损失谱(HREELS)研究催化剂表面CO分子的振动谱。结果表明,当CO的暴露量低于0.2 L (Langmuir)时,Pt/Fe/Pt(111)表面只存在顶位吸附;当暴露量大于0.4L,除了顶位吸附外,桥位吸附开始出现;顶位吸附分子的C-O键振动峰随着暴露量的增加不断向高波数方向偏移。退火温度影响Pt/Fe/Pt(111)表面CO的吸附形式,低于255K时,顶位吸附分子的脱附速率大于桥位吸附分子;高于255 K时,桥位吸附分子的脱附速率较大,并先于顶位吸附的CO从表面完全脱附,其完全脱附温度比Pt(111)表面低50 K。
基金Project supported by the Shanghai Tech University and the National Natural Science Foundation of China(Grant No.11774039)。
文摘A novel instrument that integrates reflection high energy electron diffraction(RHEED),electron energy loss spectroscopy(EELS),and imaging is designed and simulated.Since it can correlate the structural,elemental,and spatial information of the same surface region via the simultaneously acquired patterns of RHEED,EELS,and energy-filtered electron microscopy,it is named correlative reflection electron microscopy(c-REM).Our simulation demonstrates that the spatial resolution of this c-REM is lower than 50 nm,which meets the requirements for in-situ monitoring the structural and chemical evolution of surface in advanced material.
