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Study of molecule on metal nanoparticle materials with clarification function from the composite materials point of view

从复合材料的角度研究具有澄清功能的金属纳米粒子材料上的分子

基本信息

批准号：
15360358
负责人：
YAGI Shinya
金额：
$ 8.77万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

It is important to investigate an adsorption system of a sulfur-including molecule on transition metal surface. The investigation is hoped to bring a production for a new automobile catalyst, desulfurization catalyst and medicine, and also to obtain an useful knowledge. In this study, we have investigated an adsorption behaviors for L-Cysteine, (CH_3)_2S and C_2H_5SH molecules on Cu(100) or Rh(100) single crystal surfaces by means of Near-Edge X-ray Absorption Fine Structure (NEXAFS) and X-ray Photoelectron Spectroscopy (XPS) with synchrotron light. Moreover we have tried to fabricate an new functionalized thin film surface with using the Rh(PVP) nanoparticles and succeeded to find out some suitable parameters for producing the Pd nanoparticles.For the adsorption system of L-Cysteine on Cu(l00) surface, the 1^<st> layer L-Cysteine dissociates and adsorbs on the surface as the thiolate shape. In the 2^<nd> adsorption layer of L-Cysteine, the adlayer molecule has a bonding with the 1^<st … More > layer molecule. Those two L-Cysteine molecules form a dimmer molecule. For a co-adsorption molecular system of those L-Cysteine and water, the orientation angle of the S-C bonding axis changes. This result implies that the co-adsorbed water molecule has an effect on the environment of the sulfur atom of L-Cysteine. In case of the adsorption system for (CH_3)_2S and C_2H_5SH on Rh(l00) surface, there are two adsorption cases. One is thiolate molecule adsorbs on the surface. In the other case, the adsorbed molecules do not have any dissociation. Both cases much depend upon a substrate temperature. It seems about the presence of the intramolecular S-C and S-H bondings that the surface reactions have much difference and depend on the existence of those bondings. For the fabrication of the nanoparticles, we have tried to fabricate the Rh nanoparticles with using PVP (poly vinylpyrrolidone) as a surfactant molecule. Judging from the results for those Rh nanoparticles, we have succeeded to produce a thin film with many "nanoholes", which diameter is from several nm to 100 nm size. Moreover we have also succeeded to fabricate another Pd nanoparticles, which are made by the different method in comparison with the wet process. Indeed the surface of the Pd nanoparticles is not easily oxidized under the air environment at room temperature. However it clear that our fabricated Pd nanoparticles can be oxidized easily in the same condition. In addition there are some effects, which originate with the nanoparticles nature (i.e.size effect) in the obtained XPS and NEXAFS spectra. Less

研究含硫分子在过渡金属表面的吸附体系具有重要意义。希望通过本研究为新型汽车催化剂、脱硫催化剂和医药的生产带来有益的认识。本文用同步光近边X射线吸收精细结构和X射线光电子能谱研究了L-半胱氨酸、(CH_3)_2S和C_2H_5SH分子在Cu(100)或Rh(100)单晶表面的吸附行为。此外，我们还尝试用Rh(PVP)纳米粒子制备了一种新型的功能化薄膜表面，并成功地找到了制备Pd纳米粒子的一些合适的参数。对于L-半胱氨酸在铜(100)表面的吸附体系，1层L-半胱氨酸以硫酸盐的形式解离并吸附在表面。在L-半胱氨酸的2^；ND&gt；吸附层中，附着层分子与1^1；st…成键更多的层状分子。这两个L-半胱氨酸分子形成了一个较暗的分子。对于L-半胱氨酸和水的共吸附分子体系，S-C键轴的取向角发生了变化。这一结果表明，共吸附的水分子对L-半胱氨酸的硫原子环境有影响。对于(CH_3)_2S和C_2H_5SH在Rh(100)面上的吸附体系，存在两种吸附情况。一种是硫酸盐分子吸附在表面。在另一种情况下，被吸附的分子没有任何解离。这两种情况在很大程度上取决于衬底温度。对于分子内S-C和S-H键的存在，表面反应似乎有很大的不同，并取决于这些键的存在。对于纳米粒子的制备，我们尝试用PVP(聚乙烯吡咯烷酮)作为表面活性分子来制备Rh纳米粒子。从这些Rh纳米粒子的结果来看，我们已经成功地制备出了直径从几nm到100 nm大小的具有许多纳米孔的薄膜。此外，我们还成功地制备了另一种Pd纳米粒子，与湿法制备的Pd纳米粒子进行了比较。事实上，在室温的空气环境下，Pd纳米颗粒的表面不易被氧化。然而，很明显，我们制备的Pd纳米粒子在相同的条件下很容易被氧化。此外，在所获得的XPS和NEXAFS谱中还存在一些与纳米粒子性质有关的效应(即尺寸效应)。较少