Effect of oxygen adsorption and oxidation on the strain state of Pd nanocrystals

X-ray powder diffraction using a synchrotron light source reveals significant modifications to both morphology and strain state in Palladium nanocubes after oxidation. Short-range strain measured by the static component of the Debye-Waller coefficient is observed to be higher in the oxidized nanoparticles; while long-range strain related to the line broadening of the diffraction peaks is seen to decrease. Using multiscale modelling with classical molecular dynamics and density functional theory, we connect the decrease in long-range strain to the increased truncation of the oxidized nanocubes, while the higher short-range strain is shown to be due to surface softening from oxygen adsorption. Different surface disorder on different crystallographic facets lead to opposing trends for oxygen activation on the different exposed surfaces of the truncated nanoparticles.

Automated summary

X-ray powder diffraction using synchrotron light source reveals significant modifications to both morphology and strain state in Palladium nanocubes after oxidation. Short-range strain is higher in oxidized nanoparticles due to surface softening from oxygen adsorption, while long-range strain decreases as a result of increased truncation of the nanocubes. Different surface disorder on various crystallographic facets leads to opposing trends for oxygen activation on different exposed surfaces of the truncated nanoparticles.