Probing Catalytic Material Interfaces Using First Principles Simulated XAS (Prof. Tod Pascal UCSD)

Title: Probing the Structure and Electronic States of Catalytic Material Interfaces Using First Principles Based Simulated XAS
Speaker: Prof. Tod Pascal (UC San Diego)
Abstract:
Detailed mechanistic information of heterogeneous catalysis is of fundamental importance for advancing modern industrial processes that may help mitigate some of the worst effects of climate change. Much recent advances have involved fabrication and measurements on nanoscale systems, where the large surface area to volume ratio means that the ever elusive goal of having experiments and theory on similar length scales is now within reach. Spectroscopy, especially those involving high energy X-rays, is a natural link between the two, potentially providing unambiguous information about the thermodynamic states and reaction intermediates, provided that the complex spectra arising can be properly interpreted. We have recently advanced a first-principles based framework for probing the evolution of the surface structure and electronic states during a catalytic reaction using X-ray absorption spectroscopy, including the ability to model nonequilibrium processes such as electrochemical charging and the application of external electric fields. In this talk, we apply this framework to two representative cases: the carbon dioxide reduction reaction on transition-metal dichalcogenides, and modulation of small molecule binding to a perovskite by resonant surface reconstruction.