首页> 外文期刊>Advanced Functional Materials >In Situ Electrochemical Electron Microscopy Study of Oxygen Evolution Activity of Doped Manganite Perovskites
【24h】

In Situ Electrochemical Electron Microscopy Study of Oxygen Evolution Activity of Doped Manganite Perovskites

机译:掺杂锰钙钛矿的析氧活性的原位电化学电子显微镜研究

获取原文
获取原文并翻译 | 示例
           

摘要

Fundamental studies of catalysts based on manganese oxide compounds are of high interest since they offer the opportunity to study the role of variable valence state in the active state during O_2 evolution from H_2O. This paper presents a study of doping dependent O_2 evolution electrocatalysis of Pr-doped CaMnO_3 via in situ environmental transmission electron microscopy (ETEM) combined with ex situ cyclic voltammetry studies. ETEM studies of heterogeneous catalysis are a challenge, since the reactions in the H_2O vapor phase cannot directly be observed. It is shown that the oxidation of silane by free oxygen to solid SiO_(2-x) can be used to monitor catalytic oxygen evolution. Electron energy loss spectroscopy (EELS) as well as the in situ X-ray absorption study of near edge structures (XANES) in H_2O vapor reveals that the Mn valence is decreased in the active state. Careful TEM analysis of samples measured by ex situ cyclic voltammetry and an in situ bias-controlled ETEM study allows us to distinguish between self-formation during oxygen evolution and corrosion at the Pr_(1-x)Ca_xMnO_3-H_2O interface. Including density functional theory (DFT) calculations, trends in O_2 evolution activity and defect chemistry in the active state can be correclated to doping induced changes of the electronic band structure in A-site doped manganites.
机译:基于氧化锰化合物的催化剂的基础研究备受关注,因为它们提供了研究从H_2O释放O_2期间可变价态在活性态中的作用的机会。本文通过原位环境透射电子显微镜(ETEM)结合异位循环伏安法研究了Pr掺杂CaMnO_3的掺杂依赖性O_2演化电催化作用。由于无法直接观察到H_2O气相中的反应,因此ETEM研究非均相催化是一个挑战。结果表明,硅烷被游离氧氧化成固体SiO_(2-x)可用于监测催化氧的释放。电子能量损失谱(EELS)以及H_2O蒸气中近边缘结构(XANES)的原位X射线吸收研究表明,活性态Mn价降低。通过异位循环伏安法对样品进行仔细的TEM分析以及原位偏置控制的ETEM研究,使我们能够区分氧气释放过程中的自形成与Pr_(1-x)Ca_xMnO_3-H_2O界面处的腐蚀。包括密度泛函理论(DFT)计算在内,O_2演化活性和活性态缺陷化学的趋势可以与掺杂引起的A位掺杂锰电子谱带结构变化相关。

著录项

  • 来源
    《Advanced Functional Materials》 |2012年第16期|p.3378-3388|共11页
  • 作者单位

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Goettingen, Germany;

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Goettingen, Germany,Institute of Theoretical Physics Technical University of Clausthal Leibnizstr. 10, 38678 Clausthal-Zellerfeld, Germany;

    Center for Functional Nanomaterials Brookhaven National Laboratory Upton, New York 11973, USA,National Center for Electron Microscopy Lawrence Berkeley National Laboratory Berkeley, California, 94720, USA;

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Coettingen, Germany;

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Goettingen, Germany;

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Goettingen, Germany;

    Center for Functional Nanomaterials Brookhaven National Laboratory Upton, New York 11973, USA,Department of Condensed Matter Physics Brookhaven National Laboratory Upton, New York 11973, USA;

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Coettingen, Germany,Institute of Theoretical Physics Technical University of Clausthal Leibnizstr. 10, 38678 Clausthal-Zellerfeld, Germany;

    Institute of Materials Physics University of Goettingen Friedrich-Hund-Platz 1, 37077 Coettingen, Germany;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号