We present an atomistic investigation of the oxygen activation of a Pt nanoparticle with 147 atoms (Pt147), focusing on the role of microfacets. Using density functional theory (DFT) calculations, we evaluated the adsorption energy (Ead) of both molecular and atomic oxygen across the surface, along with the activation energy barrier (Eact) for O2 dissociation and subsequent atomic oxygen diffusion. The Pt147 exhibited a facet-dependent variation in O2 adsorption, while atomic oxygen displayed a relatively uniform Ead across the surface. This suggests that atomic oxygen can readily participate in surface reactions regardless of the location. The diffusion Eact values of atomic oxygen calculated along various pathways were lower than 0.61 eV, confirming the high surface mobility of oxygen atoms. Interestingly, we found a clear linear correlation between the Ead of O2 on Pt147 and the Eact of subsequent O2 dissociation. The results show that Pt nanoparticles with well-developed microfacets can efficiently activate molecular oxygen and facilitate oxidation reactions.

We use vdW-corrected density functional theory (DFT) calculations with additional electron distribution correction to study the water binding chemistry of an Au nanoparticle supported on CeO2(111) with a linear step-edge. The initial structural model of Au/CeO2 used for DFT calculations is constructed by stabilizing a Au9 nanoparticle at the linear step-edge on a CeO2(111) slab. The calculated binding energy of a water molecule clearly shows that the interfacial site between Au and CeO2 binds water more strongly than the binding sites at the surface of Au nanoparticle. Subsequent water dissociation calculation result shows that the interface-bound water can be relatively easily dissociated into–OH and –H, providing a hydroxyl group that can be utilized as an oxygen source for CO oxidation. Based on the low dissociation energy of the interface bound water molecule, we suggest that the water at the Au-CeO2 interface can facilitate further oxidation of Au-bound CO. Our results point out that Au-CeO2 interface-bound water is beneficial for low-temperature oxidation reactions such as the water-gas shift reaction or preferential CO oxidation reaction.