In situ electron yield detection of X-ray absorption fine structure of electrodes continuously emersed from electrolyte solutions

A method is described herein for the acquisition of in situ electron yield X-ray absorption fine structure (XAFS) data of solid electrodes continuously emersed from electrolyte solutions. The success of this measurement technique relies on two key features: (i) the use of a curtain-type He jet emerging from a torch blower impinging directly on the surface of the emersed electrode to decrease the thickness of the electrolyte dragged by the electrode and eliminate droplets adhered to the surface; and (ii) careful synchronization of the rates of rotation and data acquisition to average distortions derived from wobbling and surface imperfections. The capabilities of this novel strategy were illustrated using a Zn electrode continuously emersed from an alkaline solution as a model system. As is evident from the results obtained, passivation of the Zn electrode led to a shift in the Zn K-edge absorption energy toward higher values compared to metallic Zn, as would be expected for an oxidized surface. Subsequent polarization of the electrode at potentials negative enough to reduce the passive film yielded a Zn K-edge XAFS virtually identical to that observed for a conventional Zn foil recorded in the transmission mode.