Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (08): 1861-1868.doi: 10.3866/PKU.WHXB201205214

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Coverage-Dependent Adsorption of X Clusters (X=Pt-Au, Au-Au) on the Defect-Free (3×2) TiO2(110) Surface

ZHAO Wei-Na1, LIN Hua-Xiang2, LI Yi1, ZHANG Yong-Fan1, HUANG Xin1, CHEN Wen-Kai1,2   

  1. 1. College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350116, P. R. China;
    2. Fujian Provincial Key Laboratory of Photocatalysis-State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002, Fujian, P. R. China
  • Received:2012-03-20 Revised:2012-05-21 Published:2012-07-10
  • Contact: CHEN Wen-Kai E-mail:qc2008@fzu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (90922022) and Foundation of State Key Laboratory of Coal Combustion of Huazhong University of Science and Technology, China (FSKLCC1110).

Abstract:

Based on spin-polarized density functional theory and generalized gradient approximation (DFT-GGA) calculations, the coverage-dependent adsorption of X bimetallic clusters (X=Pt-Au, Au-Au) on the (3 × 2) TiO2(110) surface has been investigated utilizing periodic supercell models in the absence of oxygen vacancy sites. Only the ground-state structures corresponding to the given coverage patterns (θ= 1/6-1 ML) for X clusters are discussed in this work. The unambiguous results reveal that the adsorption energies increase with coverage up to 1/2 ML and then decrease except for when saturated coverage is reached. According to the interaction with X clusters, it is more feasible at all coverage levels to create a monolayer film of Pt-Au bimetallic clusters on the TiO2(110) surface than it is to create a monolayer of Au- Au clusters, even though the adsorption energy of the Pt-Au/TiO2 adsorption system is smaller in comparison with that of the Au-Au/TiO2 system. Importantly, especially for the half and saturated coverages, there is a broadening of X peaks overlapping with the TiO2 state ranging from -3.0 eV to the Fermi level, suggesting a strong interaction between the surface and bimetallic cluster. Also of particular interest is the adsorptive mechanism where the X-TiO2 interaction is the main driving force at the initial stage of the adsorption process, whereas the X-X interaction controls the process as the coverage increases.

Key words: Density functional theory, TiO2 (110) surface, Bimetallic cluster

MSC2000: 

  • O641