Structure dynamics at catalyst surfaces

催化剂表面的结构动力学

• 批准号: 16072204
• 负责人: IWASAWA Yasuhiro
• 金额: $ 67.01万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16072204/
• 关键词: Catalyst surface; X-ray a bsorption fine structure(XAFS); Time-resolved XAFS; Scanning tunneling microscope(STM); Direct phenol synthesis; Photo-oxidation catalysis; Catalytic reaction meachanism; In situ characterization; X線吸収微細構造; 選択酸化; In-sit

We studied the catalytically active structure, its structural transformation and dynamics, and reaction mechanism for direct phenol synthesis from benzene and molecular oxygen on a novel N-interstitial Re_<10>-cluster catalyst supported on HZSM-5 zeolite, which exhibited remarkable performances for the direct phenol synthesis. The active N-interstitial Re_<10> cluster was produced by NH_3 and it was the active species for the direct phenol synthesis using O_2 as an oxidant. Molecular oxygen (O_2) was suggested to directly react with benzene without dissociation to atomic oxygen (Ea (activation energy) = 24 kJ mol^<-1>) and the active Re cluster dynamically converted to inactive Re monomers under the reaction conditions. The structural transformation between the Re cluster and the Re monomers cycled during the phenol synthesis, whose mechanism was studied by in-situ time-resolved XAFS techniques.TiO_2 is a typical functional metal oxide which exhibits photocatalysis. Usually only ultraviolet light must be used for photochemical reactions on TiO_2 because of its bulk band gap. However, we discovered visible light photo-oxidation reactions of formic acid on the ordered lattice-work structure of a TiO_2(001) surface by using scanning tunneling microscopy (STM). Two photon photoelectron and electron energy loss spectroscopies and density functional theory calculations revealed that the nanostructured surface makes the band gap significantly smaller than 3.0 eV only at the surface layer and that the surface state of the crystal enables visible light response.

研究了以HZSM-5分子筛为载体的新型N-间隙基团簇催化剂上苯与分子氧直接合成苯酚反应的活性结构、结构转化和动力学，以及反应机理。NH_3生成的活性N-间隙Re_lt；10&Gt；团簇是以O2为氧化剂直接合成苯酚的活性物种。在该反应条件下，分子氧(O_2)直接与苯反应而不解离成原子氧(Ea(活化能)=24kJ·mol~(-1)~(-1))，活性Re原子团簇动态转化为非活性Re~(2+)。利用原位时间分辨XAFS技术研究了苯酚合成过程中Re团簇和Re单体之间的结构变化，并对其机理进行了研究。由于二氧化钛的块状带隙，通常只能用紫外光在二氧化钛上进行光化学反应。然而，我们用扫描隧道显微镜(STM)观察到了甲酸在二氧化钛(001)表面有序晶格结构上的可见光光氧化反应。双光子光电子和电子能量损失谱和密度泛函理论计算表明，纳米结构表面使带隙仅在表面层显著小于3.0 eV，并且晶体的表面态使可见光响应成为可能。

项目成果

First-Principles Theoretical Study and Scanning Tunneling Microscopic Observation of Dehydration Process of Formic Acid on a TiO2(110) Surface†

• DOI: 10.1021/jp0497460
• 发表时间: 2004-06
• 期刊: Journal of Physical Chemistry B
• 影响因子: 3.3
• 作者: Y. Morikawa;Ittetsu Takahashi;Masaki Aizawa;Y. Namai;Takehiko Sasaki;Y. Iwasawa

The Dynamic Behavior of CH_3OH and NO_2 Adsorbed on CeO_2(111) Studied by Noncontact Atomic Force Microscopy

非接触原子力显微镜研究CH_3OH和NO_2在CeO_2(111)上的动态行为

• 发表时间: 2004
• 期刊: Nanotechnology 15
• 作者: Y.Namai;K.Fukui;Y.Iwasawa
• 通讯作者: Y.Iwasawa

Enantioselective Diels-Alder Reaction Promoted by Achiral Functionalization of a SiO2-Supported Cu-BOX (Bis (oxazoline)) Catalyst

SiO2 负载 Cu-BOX（双（恶唑啉））催化剂的非手性官能化促进对映选择性 Diels-Alder 反应

• 发表时间: 2005
• 期刊: Chemistry Letters 34
• 作者: M.Tada;S.TanaKa;Y.Iwasawa
• 通讯作者: Y.Iwasawa

Advanced Catalyst Design with Supported Metal Complexes for Selective Catalysis

用于选择性催化的先进催化剂设计和负载金属配合物

• 发表时间: 2006
• 期刊: Chem. Commun.
• 作者: M.Tada;Y.Iwasawa
• 通讯作者: Y.Iwasawa

Chiral Self-Dimerization of Vanadium Complexes on a SiO2 Surface for Asymmetric Catalytic Coupling of 2-Naphthol : Structure, Performance,and Mechanism

SiO2 表面上钒配合物的手性自二聚反应用于 2-萘酚的不对称催化偶联：结构、性能和机理

• 发表时间: 2005
• 期刊: J.Phys.Chem.B 109
• 作者: M.Tada;N.KoJima;Y.lzumi;T.Taniike;Y.Iwasawa
• 通讯作者: Y.Iwasawa