Research
Chemistry Dynamics of Electrocatalysts
We pursue research questions around understanding the bulk and surface chemistry of electrocatalysts, with a focus on developing a fundamental picture of how electrocatalyst chemistry changes in aqueous and electrochemical environments. We utilize spectroscopy techniques that help us to probe surface-sensitive and atomic chemical structure, and have a key interest in disordered transition metal oxide and hydroxide materials.
Chemistry Dynamics
Surface Chemistry of Mixed Metal Oxide & Hydroxide Electrocatalysts
We are interested in understanding how the surface chemistry and bulk chemistry of mixed metal oxide and hydroxide electrocatalysts change as a function of exposure to aqueous electrochemical environments. We study chemical speciation and electronic structure of the individual components of these electrocatalysts (e.g., Fe, Ni, O) with a current focus on iron-nickel oxide nanoparticles and films. We pursue in situ electrochemical spectroscopy approaches to answer fundamental questions around how chemical structure changes, in collaboration with Prof. Jingyi Chen (Chemistry, University of Arkansas), Prof. Clemens Heske (Chemistry, University of Nevada, Las Vegas), Dr. Monika Blum (LBNL), and Dr. Tadashi Ogitsu (LLNL). One key question we are currently pursuing is whether the iron species in iron-nickel oxide bimetallic electrocatalysts remains in the 3+ oxidation state or whether the iron transitions to a higher (4+) oxidation state under oxidative conditions.
Funding: National Science Foundation and the Department of Energy, Basic Energy Sciences
Projects:
2017 – 2021: RII Track-4: In Situ and Surface Sensitive Characterization of Fe-Ni(OH)2 Bimetallic Catalysts
2020 – 2023: In Pursuit of Unambiguous Determination of Fe(III) versus Fe(IV) in Transition Metal Oxide Electrocatalysts
Chemistry Dynamics
Roles of Electrolyte Components in Electrocatalyst Surface Chemistry and Electrocatalytic Performance
Our fundamental research to develop electrocatalysts for ammonia synthesis led us to investigations around how aqueous electrolyte components (cations and anions) affect electrocatalyst surface chemistry. We are interested in understanding whether electrolyte components interact through physisorption or chemisorption mechanisms, including investigating specific and quasi-specific adsorption. We are interested in understanding the roles of both electrolyte composition and electrocatalyst composition in electrolyte-electrocatalyst interactions, and we seek to understand how chemical changes to the electrocatalyst, as a result of electrolyte exposure, impact electrocatalytic reaction kinetics and thermodynamics.
Funding: Department of Energy, Basic Energy Sciences
Project: Peptide Control of Electrocatalyst Surface Environment and Catalyst Structure: A Design Platform to Enable Mechanistic Understanding and Synthesis of Active and Selective N2 Reduction Catalysts
Chemistry Dynamics
Nanoparticle Electrocatalyst Design and Operando Chemical Structure
In collaboration with Prof. Jingyi Chen (Chemistry, University of Arkansas) and Dr. Simon Bare and Dr. Adam Hoffman (SSRL) we are exploring how the three-dimensional design of a bimetallic oxide nanoparticle affects alkaline electrolysis and the oxygen evolution half reaction. We have designed custom operando spectroscopy cells for use with synchrotron-based x-ray absorption spectroscopy to investigate how the atomic structure of the metal components changes as a function of electrochemical parameters and nanoparticle morphology. We are interested in the temporal dynamics of chemical structure in these nanoparticle electrocatalysts and seek to connect as-synthesized to operando chemical properties to better understand what properties are needed to produce optimal catalyst designs.
Funding: National Science Foundation
Project: INFEWS N/P/H2O: SusChEM: Collaborative: Controlling Spatial Composition of Nonprecious Metal-based Heteronanostructures for Enhanced Electrocatalytic Performance