Composite electrochemical catalysis utilizing mixed potential at the heterogeneous contact

利用非均相接触混合电势的复合电化学催化

基本信息

批准号：
10650729
负责人：
YAMAGUCHI Shu
金额：
$ 2.5万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650729/
关键词：
Mixed potential Ionic conductor Mixed conductor Catalysis Composite NOx DC Polarization Space Charge 触媒活性電荷移動反応交換電流密度 CO 電子構造光電子分光 NO NO_2 電気化学表面吸着

项目摘要

The present research project was aimed to develop a novel composite electrochemical catalysis which can utilize anomalous reactivity of gas species at the heterogeneous interface among porous oxide electrode with ion-electron mixed conductivity, solid electrolyte, and metallic electrode. In a microscopic scale, the catalysis is regarded as the mixture of microscaled cells with asymmetric electrode configuration that utilize so-called mixed potential, which is closely related to the space charge effect at the heterogeneous interface. In the early stage of the project, the mixture of Nd_<2-X>Ce_XCuO_4, Nd-doped CeO_2, and Au powder were examined for the catalytic activity to the NO/NO_2 Red-Ox reaction. The composite catalysis showed enhanced activity for the reaction compared to those of single component ones. It is also shown that the composite of NiO, YSZ, Au powder also showed the enhanced catalytic reaction for NOx Red-Ox. In order to examine the mechantism of the enhanced catalytic … More reaction of composites, electrochemical cells with three electrodes were examined. We found that the rate determinant steps are the mixed process of the competent absorption of NO_2 and O_2 on porous oxide and electron transfer reaction, and the simple electron transfer reaction on the Au electrode. The exchange current density of both reactions are deduced from the model. It should be noted that the relaxation of space charge, built-up at the interface of heterogeneous contact interface by both mobile ion and the adsorbed gas species is the essential mechanism for the selective enhancement of the catalytic reaction. Therefore the electronic band structure and electronic transport properties of oxides are estimated as playing important role in the formation of the mixed potential, that is one of the key to understand the anomalous reactivity of composite electrochemical catalysis. Based on these view points, the survey of possible candidates for the oxide electrode is conducted in accordance with the detailed investigation of electronic and ionic transport properties and electronic band structure by means of the photoelectron spectroscopy. As the direct reduction of NOx is difficult because of the very high activation energy, it is proposed the utilization of the proton or dissolved water in oxide electrode for the indirect reduction reaction. The detailed discussion on the oxide protonic conductors are also conducted. Less

本研究项目的目的是在氧化物之间与电子混合导向，固体电解质显微镜量表之间的异质界面开发，该催化被认为是具有不对称电极构型的显微细胞在项目的早期> CE_XCUO_4，ND掺杂的CEO_2和AU粉末的催化活性与单个成分反应相比，在NO/NO_2的反应中检查了异质界面。 NIO的复合材料，AU粉末还显示了更多的催化性红色反应。电子反应和AU电极上的简单电子转移。催化反应的含量为氧化剂的催化反应的ial机制。是理解复合电化学催化的反应性的关键之一，根据这些观点，根据电子和initonic运输和电子带结构的详细研究，对氧化物电极的可能候选者进行了调查。光谱谱系的质子分支是氧化物中的质子或氧化质量的详细讨论。