Fig. 3: Structural changes during deactivation from in situ X-ray scattering.
a Six representative small-angle X-ray scattering (SAXS) patterns (dots) showing the changes in catalyst shape over time, and corresponding fits to a model of polydisperse smooth octahedra (solid lines). The patterns are shifted for clarity. The model is fitted to the data in the grey shaded area. The change in slope of the SAXS patterns from a q–4 to a q–3 dependence indicates increased surface roughening on the 100 nm length scale. b Analytical form factor of smooth octahedra (black) and form factors based on a discrete scatterer model of octahedra with increasing surface roughness (light to dark red). c–e Simulated particles with increasingly rough octahedra (more details in Supplementary Information). In situ (surface-enhanced) Raman spectroscopy (SERS) measurements conducted on Cu2O octahedra in the f low- and g high-Raman-shift regime. Each spectrum is an average of 3 different spots acquired over a 5 min duration. The top spectrum was obtained after 120 min, and an extended version is presented in Supplementary Fig. SI23. Cartoons of the observed vibrational features for h linear adsorbed CO, i low-frequency band CO, and j bridged CO. k, l Schematic of structural changes observed with in situ X-ray scattering. Source data are provided as a Source Data file.
