title: A First-Principle Study of Synergized O2 Activation and CO Oxidation by Ag Nanoparticles on TiO2(101) Support.
abstract: We performed density functional theory (DFT) calculations to investigate the synergized O2 activation and CO oxidation by Ag8 cluster on TiO2(101) support. The excellent catalytic activity of the interfacial Ag atoms in O2 dissociation is ascribed to the positive polarized charges, upshift of Ag d-band center, and assistance of surface Ti5c atoms. CO oxidation then takes place via a two-step mechanism coupled with O2 dissociation: (i) CO + O2 → CO2 + O and (ii) CO + O → CO2. The synergistic effect of CO and O2 activations reduces the oxidation energy barrier (Ea) of reaction (i), especially for the up-layered Ag atoms not in contact with support. It is found that the coadsorbed CO and O2 on the up-layered Ag atoms form a metal-stable four-center O-O-CO structure motif substantially promoting CO oxidation. On the oxygen defective Ag8/TiO2(101) surface, because of the decreased positive charges and the down-shift of d-band centers in Ag, the metal cluster exhibits low O2 adsorption and activation abilities. Although the dissociation of O2 is facilitated by the TiO2(101) defect sites, the dissociated O atoms would cover the defects so strongly that further CO oxidation would be prohibited unless much extra energy is introduced to recreate oxygen defects.
authors.affiliation: Guizhou Provincial Key Laboratory of Computational Nano-material Science, Institute of Applied Physics and Guizhou Synergetic Innovation Center of Scientific Big Data for Advance Manufacturing Technology, Guizhou Education University , Guiyang 550018, China.|School of Chemistry and Materials Science, Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD, University of Science and Technology of China (USTC) , Hefei 230026, China.
authors.forename: Chuanyi
authors.initials: C
authors.lastname: Jia
authors.affiliation: Guizhou Provincial Key Laboratory of Computational Nano-material Science, Institute of Applied Physics and Guizhou Synergetic Innovation Center of Scientific Big Data for Advance Manufacturing Technology, Guizhou Education University , Guiyang 550018, China.|School of Chemistry and Materials Science, Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD, University of Science and Technology of China (USTC) , Hefei 230026, China.
authors.forename: Guozhen
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Guizhou Provincial Key Laboratory of Computational Nano-material Science, Institute of Applied Physics and Guizhou Synergetic Innovation Center of Scientific Big Data for Advance Manufacturing Technology, Guizhou Education University , Guiyang 550018, China.|School of Chemistry and Materials Science, Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD, University of Science and Technology of China (USTC) , Hefei 230026, China.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Zhong
authors.affiliation: Guizhou Provincial Key Laboratory of Computational Nano-material Science, Institute of Applied Physics and Guizhou Synergetic Innovation Center of Scientific Big Data for Advance Manufacturing Technology, Guizhou Education University , Guiyang 550018, China.|School of Chemistry and Materials Science, Hefei National Laboratory for Physical Sciences at the Microscale and CAS Key Laboratory of Mechanical Behavior and Design of Materials (LMBD, University of Science and Technology of China (USTC) , Hefei 230026, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
keywords: CO oxidation; O2 activation; first principle study; polarized charge; synergistic effect