Design of Robust and Reactive Nanoparticles with Atomic Precision: 13Ag-Ih and 12Ag−1X (X = Pd, Pt, Au, Ni, or Cu) Core−Shell Nanoparticles

Density functional theory calculations and a modified reaction model confirm that the initial high CO oxidation reactivity of a 13Ag-Ih nanoparticle from an icosahedron (Ih) structure is immediately diminished as the nanoparticle is transformed to an amorphous state by a reaction-driven structural change. The adsorption of O 2 and the formation of a four-center intermediate metastable state from coadsorbed CO and O 2 positively charge the 13Ag-Ih nanoparticle, and the repulsive force between the Ag atoms causes the reaction-driven structural change of the 13Ag-Ih nanoparticle. When one central Ag atom is substituted with a solute atom, a core−shell type of 12Ag−1X-Ih (X = Pd, Pt, Au, Ni, or Cu) bimetallic nanoparticle is stabilized. Among them, we propose the 12Ag−1Pd nanoparticle as a robust and reactive Ag-based bimetallic nanoparticle for CO oxidation. The results show that the structural fluxionality accounts for the catalytic activity of small nanoparticles.