Study of Pd-Au bimetallic catalysts for CO oxidation reaction by DFT calculations

Jia Zhang, Hongmei Jin, Michael B. Sullivan, Freda Chiang Huay Lim, and Ping Wu

(Received 28 August 2008; accepted 27 November 2008; published 19 January 2009)

Phys. Chem. Chem. Phys., 2009, 11, 1441-1446.

ABSTRACT:

First-principle calculations were carried out to examine the catalytic activity of Pd and Pd-Au alloy surface for CO oxidation. The influence of surface-ligand effect and lattice strain effect on activity was demonstrated. The catalytic efficiency of Pd-Au bimetallic systems depends largely on the surface composition of Pd and Au. The addition of Au significantly improves the activity of Pd-Au bimetallic slab with Au-rich surface due to the dominant Au-induced ligand effect on both O and CO chemisorption. Among various considered cases, the system with Au on the surface of the Pd₁₆Au₄ slab exhibits lowest energy barrier of 0.21 eV, which is decreased by 0.66 eV compared to that of the pure Pd (111) surface. It is predicted that the [Pd](Au) core/shell nanoparticle catalyst should have a higher activity for CO oxidation reaction as it combines the advantages of the ligand effect of Au and the strain effect of Pd.

DOI: 10.1039/b814647k