Nanozymes are nanomaterials with mimic enzyme activities. Cerium oxide nanoparticles (CNPs) are promising enzymes but display a variety of enzyme mimetic activities at the same time (superoxide dismutase, catalase, phosphatase, etc.). Control over these activities is key for this nanotechnology to be safely used in biomedicine. The size and shape of nanoparticles are factors influencing such control, but surface composition and charge (CeIV/CeIII ratio) appear to be the keys. CNPs interact strongly with phosphates but appear to selectively interact with phosphate-bearing molecules. A further issue is that phosphates may scavenge CNPs. Density Functional Theory is applied to determine the strength of such interaction with the (111), (110), (100) surfaces of CNPs. {111} surfaces are less affected by the adsorption of phosphates independently on their underlying composition, whereas {100} surfaces are those where phosphates are able to form strong surface bonds and even to displace surface species. By calculating the surface free energies as a function of phosphate concentration and temperature, we generate surface phase diagrams and predict the morphology of cerium oxide nanoparticles. We show that phosphate could be used to stabilize different CNP morphologies. Finally, we show that octahedral shaped CNPs will be better suited to protect nanoparticle activity. In contrast, the cuboidal nanoparticles will be scavenged, although they will display higher catalytic activity.

Controlling the shape of cerium oxide nanoparticles using phosphate: A density functional theory study

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.