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In Situ Electrochemical X-ray Absorption Spectroscopy of Oxygen Reduction Electrocatalysis with High Oxygen Flux
- Erickson, Evan M., Thorum, Matthew
S., Vasić, Relja, Marinković, Nebojša S., Frenkel, Anatoly I., Gewirth, Andrew A., Nuzzo, Ralph G.
- Journal of the American Chemical Society 2012 v.134 no.1 pp. 197-200
- X-ray absorption spectroscopy, carbon, chemical reduction, electrochemistry, electrodes, oxygen
- An in situ electrochemical X-ray absorption spectroscopy (XAS) cell has been fabricated that enables high oxygen flux to the working electrode by utilizing a thin poly(dimethylsiloxane) (PDMS) window. This cell design enables in situ XAS investigations of the oxygen reduction reaction (ORR) at high operating current densities greater than 1 mA in an oxygen-purged environment. When the cell was used to study the ORR for a Pt on carbon electrocatalyst, the data revealed a progressive evolution of the electronic structure of the metal clusters that is both potential-dependent and strongly current-dependent. The trends establish a direct correlation to d-state occupancies that directly tracks the character of the Pt–O bonding present.