Understanding the Role of Catalyst Microenvironment on Oxygen Evolution Performance of an Iron Porphyrin for Advanced Electrolyzer Applications

Abstract

<p>Proton-coupled electron transfer (PCET) processes are instrumental to catalytic reactions and energy applications. In this talk, I will showcase our efforts in designing and constructing a nanoscale electrochemical platform to modulate the proton and electron transfer rates independently for oxygen evolution reaction (OER). OER is the reaction that limits the performance of water electrolysers and related energy conversion technologies. Our electrocatalytic nanoplatform features a hybrid bilayer membrane (HBM) comprising of a self-assembled monolayer (SAM), an OER catalytic motif based on an iron porphyrin, a phospholipid layer, and a proton removal agent. Each of these four controls one aspect of OER, and together they dictate the overall catalytic performance. Utilizing this modular system, the electron transfer rate can be adjusted by the SAM length, and the proton removal rate can be tuned by the proton removal agent in the lipid layer [1]. By regulating the relative rates of proton and electron transfer as well as inclusion of co-cataylsts, previously we achieved higher selectivity for the four-electron process without compromising the activity of the electrocatalyst [2]. New data will also be presented on triggering proton delivery against a pH gradient [3]. In summary, our electrochemical system will provide unique insights into the optimal thermodynamic and kinetic parameters not only for oxidation catalysts [4], but also offer new opportunities to enhance the performance of other catalysts involved in fuel generation [5] and energy conversion [6] to achieve carbon neutrality and enable a circular enconomy.</p>