Study of Interface and Catalytic Activity on Core-Shell Structured Noble Metal Alloy Nanoparticles

核壳结构贵金属合金纳米粒子的界面及催化活性研究

• 批准号: 14550658
• 负责人: KOBAYASHI Yasuhiro
• 金额: $ 2.3万
• 依托单位: KYOTO UNIVERSITY (2003)Osaka Prefecture University (2002)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550658/
• 关键词: AuPd nanoparticle; core-shell structure; ultrasonic reduction technique; Mossbauer spectroscopy; EXAFS; positron annihilation; high-resolution transmission electron microscope; catalytic activity; 触媒活性; Au-Pd超微粒子; Au-Pt超微粒子; 超音波照射; 疑似コア・シェル構造

We prepared the Au-core and Pd-shell structured nanoparticles by the ultrasonic reduction technique. The diameters of the particles are about 4〜12 nm. On the core-shell structured AuPd nanoparticles, there is the high catalytic activity on hydrogenate of 4-penteonic acid. To elucidate the electronic structure of these nanoparticles, we measured ^<197>Au Mossbauer spectroscopy, EXAFS, positron annihilation and high-resolution transmission electron microscope (TEM). On ^<197>Au Mossbauer study, the spectra contain two components, one, is component due to the pure Au, and the other is due to the AuPd alloy. From the area ratio of these components, it is shown that there is the AuPd alloy layer between Au-core and Pd-shell and the thickness of the alloy layer is about 3 atom layers. The result of EXAFS on Pd K edge shows existence of the AuPd alloy layer. The expansion of the atomic distance on the Pd shell is observed by the XAFS measurements. By the positron annihilation coincidence Doppler broadening measurement (CDB), the electronic state of the surface of the nanoparticles are observed. To observe the cross section of the nanoparticles by TEM, we used the ultra microtome and developed the conditions for TEM observation.

采用超声还原法制备了金核和钯壳结构的纳米颗粒。颗粒直径约为4 ~ 12 nm。核壳结构的纳米AuPd对4-戊酸的氢化反应具有较高的催化活性。为了阐明这些纳米粒子的电子结构，我们测量了^<197>Au穆斯堡尔光谱、EXAFS、正电子湮灭和高分辨率透射电子显微镜（TEM）。在^<197>Au的穆斯堡尔研究中，光谱包含两个分量，一个是纯Au的分量，另一个是AuPd合金的分量。从这些组分的面积比可以看出，在au核和pd壳之间存在一层AuPd合金层，合金层的厚度约为3个原子层。在Pd - K边缘的EXAFS结果表明存在着AuPd合金层。通过XAFS测量，观察到Pd壳层上原子距离的膨胀。利用正电子湮灭符合多普勒展宽测量（CDB），对纳米粒子表面的电子态进行了观测。为了用透射电镜观察纳米颗粒的横截面，我们使用了超显微切片机，并建立了透射电镜观察的条件。

项目成果

Hiroe Takatani, Hiroshi Kago, Yasuhiro Kobayashi, Fuminobu Hon, Ryuichiro Oshima: "Properties of Au-Pd Nanoparticles Prepared by Sonochemical Technique"Transactions of the Materials Research Society of Japan. 28[3]. 871-874 (2003)

Hiroe Takatani、Hiroshi Kago、Yasuhiro Kobayashi、Fuminobu Hon、Ryuichiro Oshima：“通过声化学技术制备的 Au-Pd 纳米颗粒的性能”日本材料研究学会汇刊。

H.Takatani: "Positron Annihilation Study on Au-Pd Nanoparticles Prepared by Sonochemical Technique"Materials Science Forum. 445-446. 192-194 (2004)

H.Takatani：“声化学技术制备的Au-Pd纳米粒子的正电子湮灭研究”材料科学论坛。

H.Takatani: "Characterization of Noble Metal Alloy Nanoparticles Prepared by Ultrasound Irradiation"Rev.Adv.Mater.Sci.. 5. 232-238 (2003)

H.Takatani：“超声辐照制备的贵金属合金纳米颗粒的表征”Rev.Adv.Mater.Sci.. 5. 232-238 (2003)

H.Takatani, H.Kago, M.Nakanishi, Y.Kobayashi, F.Hori, R.Oshima: "Characterization of Noble Metal Alloy Nanoparticles Prepared by Ultrasound Irradiation"Rev.Adv.Mater.Sci.. 5. 232-238 (2003)

H.Takatani、H.Kago、M.Nakanishi、Y.Kobayashi、F.Hori、R.Oshima：“超声辐照制备的贵金属合金纳米粒子的表征”Rev.Adv.Mater.Sci.. 5. 232-238

大嶋隆一郎, 前田泰昭, 永田良雄: "超音波照射法による合金微粒子の合成と構造制御"ケミカルエンジニヤリング. Vol.47・No.4. 258-263 (2002)

大岛龙一郎、前田康明、永田义夫：“超声波照射法的细合金粒子的合成和结构控制”化学工程第47卷·第258-263号（2002年）。