Effect of composition and distribution on structural and surface electronic properties of palladium–gold bimetallic nanoparticles: a density functional theory investigation

Abstract

The effects of atomic composition and distribution on structural and surface electronic properties of a series of Pd–Au bimetallic nanoparticles are systematically investigated by density functional theory. We employed the 55-atom icosahedral model structure in this work. It is found that the structure with more Pd–Au bonds number presents more stability. For the Pd–Au bimetallic NPs, the electrons redistribution of the surface atoms, especially for the Au atoms, is strongly influenced by the atomic distribution. The valance d-band vacancy number of the surface Pd and Au atoms decreases due to the mixing of the two metals. In contrast to the Au atoms, the d-band center of the surface Pd changes almost linearly with the Pd composition increasing. In addition, the d-band center of the vertex atoms is closer to the Fermi level compared with that of the edge atoms in Pd n Au55−n bimetallic NPs. The investigations may be helpful in designing catalysis of Pd–Au bimetallic NPs since d-band center could be used as a general measure of local surface reactivity.