title: In situ electrochemical X-ray absorption spectroscopy of oxygen reduction electrocatalysis with high oxygen flux.
abstract: 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.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Evan M
authors.initials: EM
authors.lastname: Erickson
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Thorum
authors.forename: Relja
authors.initials: R
authors.lastname: Vasić
authors.forename: Nebojša S
authors.initials: NS
authors.lastname: Marinković
authors.forename: Anatoly I
authors.initials: AI
authors.lastname: Frenkel
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Gewirth
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Nuzzo