Ag Cluster Catalyst-Research of Reaction Mechanism and Development of Diesel deNOx Catalyst

银簇催化剂-反应机理研究及柴油脱硝催化剂开发

基本信息

批准号：
17360386
负责人：
SATSUMA Atsushi
金额：
$ 9.53万
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：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360386/
关键词：
Silver Cluster Selective Reduction of NOx Diesel engines in-situ Spectroscopy DFT calculation Active oxygen Reaction mechanism ディーゼル耐SOx性

项目摘要

Reduction of NOx from diesel engine cars is serious problem from environmental points of view. We have found that Ag duster having the Size of nano to sub-nano scale is very effective for the selective reduction of NOx by unburned hydrocarbons RIC-SCR) in the excess of oxygen. The aim of this project is to reveal the dynamics and the reaction mechanism of HC-SCR over Ag duster by using in-situ spectroscopy and DET calculations in order to guide the design of practical catalysts. The following results have been obtained in the term of the project.1.Reactivity and reaction mechanism of Ag duster : It was hind by ESR spectrometer that the contact of gaseous oxygen and Ag duster formed by a slight reduction of Ag-alumina by hydrogen results in the formation of super-oxide species. The important role of Ag duster on the activation of oxygen was clarified. Furthermore, the role of hydrogen on the activation of oxygen and the formation of Ag cluster was suggested.2. Evaluation of reaction mechanism by DFP calculation: Formation of Ag duster by hydrogen and activation of oxygen on its surface was evaluated by DFP calculation. Ag 4-membered cluster (Ag_4^<2+>) is the most stable in zeolite cage, which is in harmony with the experimental results by EKAFS. The contact of hydrogenated Ag duster (H-H-Ag_4^<2+>) with oxygen results in the formation of hydrogen peroxide. The experimental results can be rationalized by this model, because the hydrogen peroxide is active for both oxidation of hydrocarbons ns to oxygenated species and NO to NO23. SOx tolerance of Ag duster in the presence of hydrogen: High SOx tolerance of Ag duster was achieved through optimization of the kind of reductants, temperature, and co-feeding of hydrogen. The high SIX tolerance is caused by migration of SOx from Ag surface to gas phase or alumina support.

从环境的角度来看，柴油发动机汽车的NOX减少是严重的问题。我们发现，具有纳米至亚纳米尺寸的Ag duster对于过量的氧气中未燃烧的碳氢化合物ric-scr的选择性降低非常有效。该项目的目的是通过使用原位光谱和DET计算来揭示HC-SCR对Ag duster的动力学和反应机理，以指导实用催化剂的设计。在项目的任期中获得了以下结果。1。ag duster的反应性和反应机理：ESR光谱仪是由ESR光谱仪引起的，即气氧和Ag duster的接触是由于氢通过氢的略微降低Ag-alumina而形成的Ag Duster会导致超氧化物物种形成。阐明了Ag Duster在氧气激活中的重要作用。此外，提出了氢在氧气激活和Ag簇的形成中的作用。2。通过DFP计算评估反应机理：通过DFP计算评估了通过氢的形成Ag Duster和表面上的氧气激活。 Ag 4成元的簇（AG_4^<2+>）是沸石笼中最稳定的簇，它与EKAF的实验结果和谐相处。氢化Ag duster（H-H-AG_4^<2+>）与氧的接触导致过氧化氢的形成。该模型可以合理化实验结果，因为过氧化氢对于氧化为氧化物种均为氧化物种，而不是NO23。在存在氢的情况下，Ag duster的SOX耐受性：通过优化氢的还原剂，温度和共进喂养来实现Ag duster的高袜子耐受性。高六公差是由Sox从Ag表面迁移到气相或氧化铝支持引起的。