Substantial pretreatment effect on CO oxidation over controllably synthesized Au/FeOx hollow nanostructures via hybrid Au/β-FeOOH@SiO2

Bo Sun, Xinzhen Feng, Yao Yao, Qin Su, Weijie Ji*, Chak Tong AU

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

A novel synthetic strategy has been adopted to deposit Au nanoparticles (NPs) (ca. 5 nm) on a hollow FeOx substrate using Au/β-FeOOH hybrid nanocrystals as the precursor. Through the encapsulation of Au/β-FeOOH by SiO2 shells and the calcination step, the Au/β-FeOOH can be transformed into Au/FeOx with the hollow structural feature. Because of the protective SiO2 shells, aggregation of the Au NPs is effectively prohibited, and the hemispherical morphology of the Au particles is essentially retained. The Au/FeOx hollow composite is obtained by removing the SiO2 shells, and the Au NPs in the final Au/FeOx hollow composite are small-sized yet stable enough because of the calcination history. The derived Au/FeOx hollow composite shows a substantial pretreatment effect on CO oxidation: with a pretreatment in the reaction feed at 180 C for 0.5 h, the hollow Au/FeO x shows the T100 of CO oxidation decreasing from 180 to 88 C. O2 temperature-programmed desorption and X-ray photoelectron spectroscopy characterizations revealed that the pretreatment may result in (i) the creation of electron holes in the p-type FeOx substrate and electron deficiency of Au nanoparticles as well as a strong Au-FeOx interaction; (ii) appropriate coverage of oxygen adspecies on the Au NPs; and (iii) increased surface oxygen density, especially at the Au-FeOx boundary region, as a result of the spillover effect of oxygen adspecies from Au NPs. All of these features are responsible for an overall enhanced activity of CO oxidation and better durability of the Au/FeOx hollow composite.

Original languageEnglish
Pages (from-to)3099-3105
Number of pages7
JournalACS Catalysis
Volume3
Issue number12
DOIs
Publication statusPublished - 6 Dec 2013

Scopus Subject Areas

  • Catalysis
  • Chemistry(all)

User-Defined Keywords

  • akagenite
  • CO oxidation
  • gold
  • hematite
  • hollow nanostructures
  • pretreatment effect

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