The effect of co-adsorbed H₂O₂, CO₂ and H₂O on CeO₂ nanoparticle morphology: A density-functional theory study

CeO₂ is an important catalyst for a variety of industrial and biomedical applications. Control over the morphology and surface speciation is key to obtaining the desired reactivity, but both are a complex function of the temperature and the partial pressures of oxygen and any adsorbates present. In this work, we combine first-principles calculations to model the individual and co-adsorption of H₂O₂, CO₂ and/or H₂O at the {100}, {110} and {111} surfaces of stoichiometric and O-deficient CeO_2, and to explore the impact of environmental conditions on the morphology and surface speciation of CeO₂ nanoparticles. We find that the presence of multiple adsorbates can render different particle morphologies accessible and stabilise or exclude adsorbates from the exposed surfaces. More generally, our modelling approach provides a powerful route to interpreting, predicting and optimising the catalytic behaviour of CeO₂, and one that can be readily extended to other materials and adsorbates.