CO oxidation catalyzed by Au-Ag bimetallic nanoparticles supported in mesoporous silica

Chun Wan Yen, Meng Liang Lin, Aiqin Wang, Shin An Chen, Jin Ming Chen, Chung Yuan Mou

Research output: Contribution to journalArticlepeer-review

156 Citations (Scopus)

Abstract

We report a novel Au - Ag bimetallic nanocatalyst supported on an acidic mesoporous aluminosilicate Au-Ag@APTS-MCM prepared by a two-step synthesis procedure, which is very active for low-temperature CO oxidation. Its catalytic activity is still quite appreciable after 1 year of storage under room conditions. The silane APTS [H2N(CH2)3-Si(OMe) 3] was used to surface functionalize mesoporous silica. The functionalized mesoporous silica was used to absorb the gold precursor AuCl 4- and silver precursor AgNO3 to form gold-silver bimetallic nanoparticles inside the nanochannels after chemical reduction. The catalysts were activated by calcinations, followed with hydrogen reduction at 873 K. Using various characterization techniques, such as X-ray diffraction, UV-vis, transmission electrom microscopy, and X-ray absorption fine structure spectroscopy (EXAFS), we elucidated the structure and surface compositions. As compared with the previously reported Au-Ag@MCM, prepared by one-pot procedure, the new method yields smaller sizes of AuAg bimetallic nanoparticles (4-6 vs 20 nm). They exhibited higher activity in catalysis for low-temperature CO oxidation with high stability. Moreover, the catalyst is resistant to moisture over a long storage time. A synergetic effect in relative composition was also found. The EXAFS study shows that Ag predominantly resides on the surface of the bimetallic nanoparticle. This distribution helps to yield a catalyst that is very active in both CO and O2 neighboring sites.

Original languageEnglish
Pages (from-to)17831-17839
Number of pages9
JournalJournal of Physical Chemistry C
Volume113
Issue number41
DOIs
Publication statusPublished - 2009
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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