Development of the dynamical structure analysis method of reaction intermediates by means of time-resolved XAFS

时间分辨XAFS反应中间体动力学结构分析方法的发展

• 批准号: 11440180
• 负责人: NOMURA Masaharu
• 金额: $ 3.58万
• 依托单位: High energy accelerator research organization
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11440180/
• 关键词: dispersive XAFS; time-resolved XAFS; Cu0ZSM-5 catqalyst; catalysis

A compact mirror bender and a mirror, which can be installed in a dispersive XAFS experimental system, were developed. The mirror system is used to focus the beam vertically and reduce the higher order content. Triangular polychomator crystals and the bender system for it was used at first, but a new rectangular polychromator crystal and a bender to realize elliptical shape is newly developed in order to achieve smaller focus size at the sample position. The focus sizes were evaluated. A coupling optics system to meet the requirement of kinetics mode of a CCD detector is also developed.Cu-ZSM-5 catalyst is well known that it has unique catalytic property for NO decomposition and its activity is related to the redox reaction of copper species. The time resolved reduction process of copper cations in ZSM-5 during temperature-programmed reduction (300-700K) was studied by using the energy-dispersive XAFS system developed in this research with 1 sec. time-resolution. The isolated Cu^<2+> species in the channel were reduced stepwise. They were reduced to isolated Cu^+ species at 400-450 K, then to Cu^0 metallic clusters at 550-650K.Small clusters like Cu_4 were initially formed, followed by particle growth. A small part of them went out to the outer surfaces of ZSM-5 during the reduction.Preliminary experiment of solution reaction by using sropped-flow apparatus was also carried out. It is confirmed that fairly high quality data can be obtained by using the system developed in this research.

研制了一种可安装在色散XAFS实验系统中的小型弯镜器和反射镜。反射镜系统用于垂直聚焦光束并减少高阶含量。最初使用三角形多色晶体及其弯曲系统，但新开发了新的矩形多色晶体和实现椭圆形状的弯曲器，以便在样品位置实现更小的焦点尺寸。对病灶大小进行了评价。Cu-ZSM-5催化剂对NO的分解具有独特的催化性能，其活性与铜物种的氧化还原反应有关。利用自行研制的能量色散X射线荧光光谱系统，研究了程序升温还原过程中（300- 700 K）ZSM-5分子筛中铜离子的时间分辨还原过程。时间分辨率通道中孤立的Cu^<2+>物种被逐步还原。在400-450 K时，它们被还原成孤立的Cu^+，在550- 650 K时，它们被还原成Cu^0金属团簇，并在随后的过程中形成了类似于Cu_4的小团簇，随后颗粒长大。在还原过程中，有一小部分逸出到ZSM-5的外表面。实践证明，使用本研究开发的系统可以获得相当高质量的数据。

项目成果

山口有朋 他: "時間分解DXAFS法によるCu/ZSM-5触媒の還元過程に関する研究"触媒. 42. 419-421 (2000)

Aritomo Yamaguchi 等：“通过时间分辨 DXAFS 方法研究 Cu/ZSM-5 催化剂的还原过程”，《催化》42. 419-421 (2000)。

A.Yamaguchi, T.Shido, Y.Inada, Y.Kogure, K.Asakura, M.Nomura and Y.Iwasawa: "Time-resolved DXAFS Study on the reduction processes of Cu cations in ZSM-5"Catal. Lett.. 68. 139-145 (2000)

A.Yamaguchi、T.Shido、Y.Inada、Y.Kogure、K.Asakura、M.Nomura 和 Y.Iwasawa：“ZSM-5 中铜阳离子还原过程的时间分辨 DXAFS 研究”目录。

T.Shido, A.Yamaguchi, Y.Inada, K.Asakura, M.Nomura and Y.Iwasawa: "DXAFS study on the decarbonylation process of Mo(CO)_6 in NaY supercage"J.Synchrotron Rad.. 8. 628-630 (2001)

T.Shido、A.Yamaguchi、Y.Inada、K.Asakura、M.Nomura 和 Y.Iwasawa：“NaY 超笼中 Mo(CO)_6 脱羰过程的 DXAFS 研究”J.Synchrotron Rad.. 8. 628

A.Yamaguchia et al.: "Time-resolved DXAFS study on the reduction process of Cu cations in ZSM-5"Catalysis Letters. 68. 139-145 (2000)

A.Yamaguchia 等人：“ZSM-5 中铜阳离子还原过程的时间分辨 DXAFS 研究”催化快报。

野村 昌治: "時分割XAFS"放射光. 13. 319-321 (2000)

Shoji Nomura：“时分 XAFS”同步加速器辐射。13. 319-321 (2000)