| AVS 56th International Symposium & Exhibition | |
| Surface Science | Monday Sessions |
| Session SS2-MoA |
| Session: | Formation & Reactivity of Nanoclusters |
| Presenter: | F. Tao, Lawrence Berkeley National Lab |
| Authors: | F. Tao, Lawrence Berkeley National Lab M. Grass, Lawrence Berkeley National Lab D. Butcher, Lawrence Berkeley National Lab J.R. Renzas, Lawrence Berkeley National Lab Y. Zhang, Lawrence Berkeley National Lab C. Tsung, Lawrence Berkeley National Lab S. Aloni, Lawrence Berkeley National Lab M. Salmeron, Lawrence Berkeley National Lab G.A. Somorjai, Lawrence Berkeley National Lab |
| Correspondent: | Click to Email |
The bimetallic catalyst is one important category of heterogeneous catalysts for numerous industrial processes and energy conversion. Surface structure and chemistry of three bimetallic catalysts, Rh-Pd, Rh-Pt, and Pd-Pt nanoparticles during catalysis, oxidation, and reducing reactions have been systematically studied in-situ using XPS in a Torr pressure range and high resolution TEM. The RhxPd1-x and RhxPt1-x nanoparticles undergo reversible changes in both atomic fractions and chemical states corresponding to the switch of reaction environments between oxidizing and reducing conditions. Rh atoms in RhxPd1-x and RhxPt1-x segregate to surface layers and are largely oxidized in oxidizing conditions while in reducing atmospheres the Pd atoms in RhxPd1-x and Pt atoms in RhxPt1-x diffuse to the surface regions and Rh atoms are largely reduced. In contrast to RhxPd1-x and RhxPt1-x, no significant segregation of Pd or Pt atoms was found in PtxPd1-x nanoparticles; Pd atoms are alternatively oxidized and reduced under oxidizing and reducing conditions, whereas Pt atoms do not. The capability of restructuring nanoparticles through chemical reactions illustrates the flexibility of the structure of bimetallic nanoparticle catalysts and suggests a new method for the development of new catalysts.
Reference: F. Tao et al. 322, 932 (2008)