Department Seminar

Upcoming Seminar

Energy Storage and Conversion: The Coupling Between Ion Insertion and Surface Reactivity in Oxygen Electrocatalysis
Dr. J. Tyler Mefford, UC Santa Barbara

February 18, 2026
4:00pm-5:00pm in HSCI-105

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Abstract

Electrocatalytic oxygen reduction and evolution reactions (ORR/OER) underpin technologies for hydrogen production and use, metal-air batteries, and electrochemical synthesis. In emerging catalyst classes, including transition metal (oxy)(hydr)oxides and organic mixed ionic-electronic conducting polymers (OMIECS), reactivity is not governed solely by static surface adsorption energetics. Instead, these materials undergo voltage-dependent ion insertion reactions that dynamically modulate their bulk and surface composition, electronic structure, and physical structure. As a result, their catalytic states are inherently far from equilibrium and there is direct coupling between ion insertion (i.e., "charge storage") and oxygen electrocatalysis (i.e., "charge conversion").

In this talk, I will present a framework to understand and quantify this bulk–surface coupling by integrating electroanalytical measurements with operando X-ray, vibrational, and scanning probe microscopies. These multiscale experiments connect atomic-scale transformations to device-level behavior and inform first-principles calculations and steady-state microkinetic models that explicitly account for voltage-dependent surface coverages and bulk compositional changes.

Using β-Co(OH)₂, α-MnO2, and perovskite oxides as model transition metal platforms, I will show how ion insertion reshapes active sites and enables new catalytic pathways. Complementary studies of OMIECs reveal an analogous paradigm in which electrochemical doping (polaron formation via ion insertion) mediates oxygen reduction through mechanisms distinct from traditional surface-adsorptive routes. In both material classes, activity and selectivity emerge from the interplay between bulk redox chemistry and interfacial kinetics. Together, this approach reframes oxygen electrocatalysts as dynamic system.

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