Abstract
Gas reactions studied by in situ electron microscopy can be used to capture the real-time morphological and microchemical transformations of materials at length scales down to the atomic level. In situ closed-cell gas reaction (CCGR) studies performed using (scanning) transmission electron microscopy (STEM) can separate and identify localized dynamic reactions, which are extremely challenging to capture using other characterization techniques. For these experiments, we used a CCGR holder that utilizes microelectromechanical systems (MEMS)-based heating microchips (hereafter referred to as "E-chips"). The experimental protocol described here details the method for performing in situ gas reactions in dry and wet gases in an aberration-corrected STEM. This method finds relevance in many different materials systems, such as catalysis and high-temperature oxidation of structural materials at atmospheric pressure and in the presence of various gases with or without water vapor. Here, several sample preparation methods are described for various material form factors. During the reaction, mass spectra obtained with a residual gas analyzer (RGA) system with and without water vapor further validates gas exposure conditions during reactions. Integrating an RGA with an in situ CCGR-STEM system can, therefore, provide critical insight to correlate gas composition with the dynamic surface evolution of materials during reactions. In situ/operando studies using this approach allow for detailed investigation of the fundamental reaction mechanisms and kinetics that occur at specific environmental conditions (time, temperature, gas, pressure), in real-time, and at high spatial resolution.
| Original language | English |
|---|---|
| Article number | e62174 |
| Journal | Journal of Visualized Experiments |
| Volume | 2021 |
| Issue number | 173 |
| DOIs | |
| State | Published - Jul 2021 |
Funding
This research was primarily sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL), managed by UT-Battelle LLC, for the U.S. Department of Energy (DOE). Part of the development to introduce water vapor into the in situ gas cell was sponsored by the U.S. DOE, Office of Energy Efficiency and Renewable Energy, Bio-Energy Technologies Office, under contract DE-AC05-00OR22725 (ORNL) with UT-Battle, LLC, and in collaboration with the Chemical Catalysis for Bioenergy (ChemCatBio) Consortium, a member of the Energy Materials Network (EMN). This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. DOE under Contract No. DE-AC36-08GO28308. Part of the microscopy was conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. Early development of in situ STEM capabilities was sponsored by the Propulsion Materials Program, Vehicle Technologies Office, U.S. DOE. We thank Dr. John Damiano, Protochips Inc., for useful technical discussions. The authors thank Rosemary Walker and Kase Clapp, ORNL production team, for support with movie production. The views expressed in this article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http:// energy.gov/downloads/doe-public-access-plan).
| Funders | Funder number |
|---|---|
| Chemical Catalysis for Bioenergy | |
| Energy Materials Network | |
| U.S. Government | |
| U.S. Department of Energy | |
| Office of Science | |
| Office of Energy Efficiency and Renewable Energy | |
| Oak Ridge National Laboratory | |
| National Renewable Energy Laboratory | DE-AC36-08GO28308 |
| Bioenergy Technologies Office | DE-AC05-00OR22725 |
| UT-Battelle |