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Volumn 301, Issue 5635, 2003, Pages 935-938

Active nonmetallic Au and Pt species on ceria-based water-gas shift catalysts

Author keywords

[No Author keywords available]

Indexed keywords

CATALYST ACTIVITY; GOLD; NANOSTRUCTURED MATERIALS; PLATINUM;

EID: 0042242562     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.1085721     Document Type: Article
Times cited : (2771)

References (30)
  • 8
    • 0038821293 scopus 로고    scopus 로고
    • A. Trovarelli, Ed., Catalytic Science Series, Imperial College Press, London
    • M. Shelef, G. W. Graham, R. W. McCabe, in Catalysis by Ceria and Related Materials, A. Trovarelli, Ed., Catalytic Science Series, vol. 2 (Imperial College Press, London, 2002), pp. 343-376.
    • (2002) Catalysis by Ceria and Related Materials , vol.2 , pp. 343-376
    • Shelef, M.1    Graham, G.W.2    McCabe, R.W.3
  • 15
    • 0043282760 scopus 로고    scopus 로고
    • note
    • After heating in He to the desired temperature, the reaction gas mixture was introduced in a flow microreactor that contained a packed-bed of catalyst particles (<50 μm in size). Rates were measured for 2 hours at each temperature, and only steady-state data are reported. Measurements were conducted with the same catalyst charge in descending temperature mode; upon completion of the series of runs, the rate was measured again at 300°C. The new value was within 5% of the initial rate at this temperature.
  • 16
    • 0041779524 scopus 로고    scopus 로고
    • note
    • Materials and methods are available as supporting material on Science Online.
  • 17
    • 0043282755 scopus 로고    scopus 로고
    • note
    • Initial- and final-state effects on the binding energy of Au clusters on ceria are not available in the literature. Generally, final-state effects cause a positive shift of the binding energy of metallic nanoparticles as their size is decreased (18), but below a certain cluster size (∼2 nm), initial-state effects prevail (19), causing negative binding energy shifts. Therefore, extensive compensation effects are possible. The observed minor, positive energy shift may be due to partially oxidized Au clusters.
  • 24
    • 0042280467 scopus 로고    scopus 로고
    • note
    • 3/ min (NTP)] was passed over the sample, which was heated at 5°C per min to 900°C. The effluent gas was analyzed by mass spectrometry (MKS model RS-1). The cyclic CO-TPR experiments were conducted only up to 400°C to avoid structural changes in the catalyst at higher temperatures.
  • 25
    • 0042280466 scopus 로고    scopus 로고
    • note
    • 2 calcined at 800°C (Table 1). These values will increase if Au or Pt ions substitute in the ceria lattice.
  • 30
    • 0041779526 scopus 로고    scopus 로고
    • note
    • We gratefully acknowledge the suport of this work by the National Science Foundation and the U.S. Environmental Protection Agency, under grant no. CTS 9985305.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.