Observing Dynamic Chemical Processes in Gases and Liquids by Operando Scanning Transmission Electron Microscopy Seminar
- Time:
- 11:00
- Date:
- 9 March 2018
- Venue:
- Building 27, Room 2001, Chemistry, University of Southampton
For more information regarding this seminar, please email Dr Nuria Garcia-Araez at N.Garcia-Araez@soton.ac.uk .
Event details
Seminar with Prof Nigel Browning, University of Liverpool
Many processes in materials engineering, physics, chemistry and biology take place in a liquid or gas environment. In these cases, the final desired outcome of the process is a result of a series of complicated transients, where a change in the order, magnitude or location in each of the steps in the process can lead to a radically different result. Understanding and subsequently controlling the final outcome, for example in the design of an efficient catalyst or energy storage system, therefore requires the ability to directly control and observe the kinetics of these transients as they happen. The transmission electron microscope (TEM) has the potential to observe precisely these kinetic processes on the atomic and molecular scale. To accomplish this, in-situ gas and liquid stages are incorporated into the microscope and images are acquired under a compressive sensing/machine learning optimization of the dose/data content. In this presentation, the unique in-situ methodologies employed to study dynamic electrochemical reactions in the aberration corrected scanning transmission electron microscope (STEM) at the University of Liverpool will be described. New results showing the use of in-situ liquid stages to study nucleation and growth using inpainting will be presented and the potential insights that can be gained by increasing the image acquisition speed and/or decreasing the electron dose will be described. Importantly for all in-situ observations, the kinetic control of the nucleation and growth process using sub-sampling highlights the role of interfaces in controlling the process. Sub-sampling and inpainting is not limited to STEM (or even to electron microscopy) as similar methods can be used in TEM mode to increase the speed of any camera. The potential to apply these methods together to extract quantitative image information from a wide range of images used for engineering/medical applications will also be discussed.
Speaker information
Prof Nigel Browning, University of Liverpool. Nigel Browning is currently Chair of Electron Microscopy at the University of Liverpool. He received his BSc from the Reading University and Ph.D from the Cambridge University, both in physics. He joined Oak Ridge National Laboratory in 1992 as a postdoc before taking a faculty position in Physics at the University of Illinois at Chicago in 1995. In 2002, he joined Chemical Engineering and Materials Science at the University of California-Davis (UCD) and also held a joint appointment in the National Center for Electron Microscopy at Lawrence Berkeley National Laboratory. In 2005, he moved his joint appointment to Lawrence Livermore National Laboratory (LLNL) to become the Dynamic Transmission Electron Microscope (DTEM) project leader. In 2009, he also joined the Dept. of Molecular & Cellular Biology at UCD to focus on the development of the DTEM to study live biological structures. From 2011-2017 he was a Laboratory Fellow and Lead of the Chemical Imaging Initiative at the Pacific Northwest National Laboratory. He has over 25 years of experience in the development of new methods in electron microscopy for high spatial, temporal and spectroscopic resolution. His research has been supported by DOE, NSF, NIH, DOD and by industry, leading to research projects for over 30 graduate students and 35 postdocs. He is a Fellow of the American Association for the Advancement of Science (AAAS) and the Microscopy Society of America (MSA). He received the Burton Award from the MSA in 2002 and the Coble Award from the American Ceramic Society in 2003 for the development of atomic resolution methods in scanning transmission electron microscopy (STEM). With colleagues at LLNL he also received R&D 100 and Nano 50 Awards in 2008, and a Microscopy Today Innovation Award in 2010 for the development of the DTEM. He has over 350 publications (h-index=69) and has given over 330 invited presentations on advanced TEM methods.