Advanced Scanning Electrochemical Microscopy of Single-Crystal Oxygen Electrocatalysis

This research centers on the development of new electrochemical microscopy methods, grounded in quantitative microkinetic modeling, to identify reactive intermediates and reaction pathways in oxygen electrocatalysis. This project aims to develop an advanced quantitative understanding of oxygen electrocatalysis, which is crucial for various electrochemical technologies with important practical applications, including the efficient production and utilization of energy. Reliable identification of the molecular mechanism of oxygen electrocatalysis is urgently needed not only to understand the highly complex coupling among multiple electron-transfer and adsorption events but also to design superior electrocatalysts that facilitate or accelerate intermediate steps, thereby minimizing energy loss from large overpotentials. Both graduate and undergraduate students will be recruited and trained through international and industrial collaborations to develop new electrocatalysts not only for the proposed research but also for the advanced manufacturing of potential commercial products. This project focuses on the quantitative study of both oxygen evolution and reduction reactions to resolve the intermingled pathways of the four-step, four-electron reactions. New electrochemical methods developed will provide an unprecedented opportunity to resolve complex multistep reactions into elementary steps. Specifically, the research group will develop and apply transient voltammetry based on scanning electrochemical microscopy to separately determine the thermodynamic and kinetic parameters of each electron-transfer and adsorption step. Reliable reaction parameters will be obtained by employing clean single-crystal metals and alloys with well-defined surface-atom arrangements. Oxygen electrocatalysis will also be spatially resolved to identify the most reactive region on the curved surfaces of single-crystal spheres, as represented by Pt, Pt alloys, and Ni–Fe oxyhydroxide, in acidic and alkaline media. Multidimensional volcano plots will be constructed using experimentally determined reactivities and adsorption energies of all intermediates to guide the rational design of superior electrocatalysts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.