Anomalous small-angle X-ray scattering (ASAXS) of synchrotron radiation with X-ray energies near the Pt-L
3 X-ray absorption edge was used to examine the size distribution of nanometer-sized catalyst particles in porous electrodes for electrocatalytic applications. Carbon-supported platinum electrocatalysts with 5–80 wt% Pt were studied in situ in an electrochemical cell with a 1 M sulfuric acid electrolyte. The anodic oxidation was found to shift the particle size distribution from a mean size of 1.7 nm in the reduced state to 2.1 nm for a 10 wt% Pt/C catalyst. From the size increase, one can infer the formation of oxide shells at the particle surfaces with layer thicknesses of about 1 nm.
<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>
We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.
Direct Observation of the Xenon Physisorption Process in Mesopores by Combining In Situ Anomalous Small-Angle X-ray Scattering and X-ray Absorption Spectroscopy