Ionic Current Mn K-Edge X-ray Absorption Spectra Obtained in a Flow Cell

Abstract

Ionic current X-ray absorption spectroscopy (IC-XAS) relaying on the synchrotron beam-induced ionization current was recently proposed as an alternative approach for XAS detection in flow cells. In this study, we investigate the mechanism behind IC-XAS by varying the spacer thickness and the cell orientation. On the basis of these studies, we propose that the driving force for the ionic current is a beam-induced electric potential between the two electrodes. After that, we attempt to detect IC-XA spectra from the Mn K-edge of several manganese salts, specifically nitrate, chloride, sulfate, acetate, and permanganate. We find that Mn K-edge IC-XAS spectra of aqueous Mn ions can be affected by the mass and concentration of the anions, the substrate as well as the beam intensity. Potential applications and limitations of this method are discussed.