Au/Co 3O 4-TiO 2 catalysts for preferential oxidation of CO in H 2 stream

Yu Wen Chen, Hsin Ju Chen, Der Shing Lee

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

A series of Au catalysts supported on Co 3O 4-TiO 2 with various Co contents were prepared. Co 3O 4-TiO 2 support was prepared by incipient-wetness impregnation with aqueous solution of Co(NO 3) 3 on TiO 2. Gold catalyst was prepared by deposition-precipitation at pH 7 and 65 °C. The catalysts were characterized by ICP-MS, XRD, TEM, HRTEM and XPS. The catalytic performance of these catalysts was investigated by preferential oxidation of carbon monoxide in hydrogen stream (PROX). The reaction was carried out in a fixed bed reactor with feed of CO:O 2:H 2:He = 1.33:1.33:65.33:32.01 (volume ratios). Au/TiO 2 catalyst had both high CO oxidation activity and high H 2 oxidation activity. Adding suitable amount of Co 3O 4 on Au/TiO 2 could enhance CO conversion to a higher extent and suppress H 2 oxidation. On Au/TiO 2 catalysts, gold nucleates at oxygen defect sites of anatase TiO 2 and remains highly dispersed and in good contact with the support. The gold atoms directly in contact with TiO 2 are positively charged and highly stable. Doping with cobalt oxide increases the number of oxygen defects on TiO 2, thus leading to a higher concentration of strongly bound gold atoms. The amorphous nature of Co 3O 4 along with TiO 2 not only enhances electronic interaction between Au and Co 3O 4-TiO 2, but also stabilizes the nano-size gold particles, thereby enhancing the catalytic activity of CO towards higher extent.

Original languageEnglish
Pages (from-to)470-480
Number of pages11
JournalJournal of Molecular Catalysis A: Chemical
Volume363-364
DOIs
StatePublished - Nov 2012

Keywords

  • Co O
  • CO oxidation
  • Gold catalyst
  • Hydrogen energy
  • PROX
  • TiO

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