04/02/2024
By Zhiyong Gu
Title: Predicting Bimetallic Catalyst Reconstruction and Performance from Molecular-Surface Interactions
Prof. Alyssa Hensley
Department of Chemical Engineering and Materials Science, Stevens Institute of Technology
Abstract:
To sustainably address our energy and chemical needs, new fundamental chemistries and technologies are required that will enable creation of new “oil” and chemical feedstocks from carbon neutral sources like biomass. This requires effective multi-functional catalysts as the biomass-derived feedstocks are highly diverse. Multi-metallic catalysts leverage the properties of multiple metal components to offer improved catalytic performance for a range of applications, but the rapid and rational design of such catalysts is complicated by the tendency of such catalysts to reconstruct in response to the high adsorbate coverages present under realistic reaction conditions. Thus, there is a critical need for fundamental insight into the interplay between adsorbate-adsorbate, adsorbate-metal, and metal-metal interactions, as such interactions provide the driving force for surface reconstructions. Here, we combine density functional theory with microkinetic modeling to predict the nanoscale interplay between reaction environment and surface reconstruction in bimetallic catalysts at the nanoparticle level via two case studies. First, we demonstrate the power of our multiscale modeling approach by capturing the cyclic reconstruction of RhPd nanoparticles through exposure to oxidizing and reducing conditions and benchmarking the resulting models against experiments. Second, we extend our approach to the study of PtM bimetallic nanoparticles under hydrogen oxidation conditions, identifying periodic trends in nanoscale energies as well as nanoparticle reconstruction patterns. Overall, this work provides us a deeper understanding of how the nanoscale interactions between adsorbates and bimetallic surfaces drive the metal and adsorbate distributions on catalyst surfaces, as well as enable the real-world tuning of surface composition in bimetallic surfaces via reaction environment.
Biography:
Alyssa Hensley received her Ph.D. from Washington State University in 2015 under the mentorship of Jean-Sabin McEwen. After obtaining her Ph.D., Hensley had the opportunity to collaborate closely with Charles Sykes (Tufts University), a leading expert in the bridging of surface science and heterogeneous catalysis, and so remained at WSU as a postdoc. In 2018, Hensley joined the group of Prof. Cathy Chin at the University of Toronto as a postdoctoral fellow, where she combined kinetic-isotopic experiments with ab initio computational simulations to quantify the atomistic effects of solid-liquid interfaces on the catalytic mechanisms for upgrading biomass-derived phenols to value-added chemicals. Since 2021, Hensley has been an assistant professor in the Department of Chemical Engineering and Materials Science at Stevens Institute of Technology. Currently, Hensley’s research uses multi-scale computational modeling techniques to address the knowledge-gap in our ability to connect the in situ chemical composition and structure of heterogeneous catalysts to the selective activation of chemical bonds.