通过二次电子成像和透射电子成像同时原位加热来了解催化剂行为。

Understanding catalyst behavior during in situ heating through simultaneous secondary and transmitted electron imaging.

作者信息

Howe Jane Y, Allard Lawrence F, Bigelow Wilbur C, Demers Hendrix, Overbury Steven H

机构信息

Physical Sciences Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Rd, TN 37831 Oak Ridge, USA ; Hitachi High-Technologies Canada Inc, 89 Galaxy Blvd, Toronto, ON M9W 6A4, Canada.

Physical Sciences Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Rd, TN 37831 Oak Ridge, USA.

出版信息

Nanoscale Res Lett. 2014 Nov 14;9(1):614. doi: 10.1186/1556-276X-9-614. eCollection 2014.

DOI:10.1186/1556-276X-9-614

PMID:25419195

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC4236855/

Abstract

By coupling techniques of simultaneous secondary (SE) and transmitted electron (TE) imaging at high resolution in a modern scanning transmission electron microscope (STEM), with the ability to heat specimens using a highly stable MEMS-based heating platform, we obtained synergistic information to clarify the behavior of catalysts during in situ thermal treatments. Au/iron oxide catalyst 'leached' to remove surface Au was heated to temperatures as high as 700°C. The Fe2O3 support particle structure tended to reduce to Fe3O4 and formed surface terraces; the formation, coalescence, and mobility of 1- to 2-nm particles on the terraces were characterized in SE, STEM-ADF, and TEM-BF modes. If combined with simultaneous nanoprobe spectroscopy, this approach will open the door to a new way of studying the kinetics of nano-scaled phenomena.

摘要

通过在现代扫描透射电子显微镜（STEM）中耦合高分辨率同时二次电子（SE）和透射电子（TE）成像技术，并利用基于微机电系统（MEMS）的高度稳定加热平台对样品进行加热的能力，我们获得了协同信息，以阐明原位热处理过程中催化剂的行为。将经过“浸出”以去除表面金的金/氧化铁催化剂加热到高达700°C的温度。Fe2O3载体颗粒结构倾向于还原为Fe3O4并形成表面台阶；在SE、STEM-ADF和TEM-BF模式下对台阶上1至2纳米颗粒的形成、聚结和迁移进行了表征。如果与同步纳米探针光谱相结合，这种方法将为研究纳米尺度现象的动力学开辟一条新途径。