Effect of the activation temperature on the state of gold supported on titania: An FT-IR spectroscopic study - Archive ouverte HAL
Article Dans Une Revue Applied Catalysis A : General Année : 2006

Effect of the activation temperature on the state of gold supported on titania: An FT-IR spectroscopic study

Résumé

The effect of the pre-treatment conditions on the evolution of gold species on an Au/TiO2 sample prepared by deposition–precipitation with urea has been followed by FT-IR spectroscopy of adsorbed CO. Gold is in the form of Au3+ species on the as-prepared sample and is not affected by evacuation at ambient temperature. However, the Au3+ species are readily reduced by CO at ambient temperature giving rise immediately to Au+ cations (the corresponding carbonyls displaying a band at 2168 cm−1), which are then slowly converted into metallic gold (carbonyl band at around 2106 cm−1). The Au3+ species are reduced to metal gold (respective carbonyl bands in the 2135–2100 cm−1 region) when a fresh sample is heated at T ≥ 473 K. Water was found to affect CO adsorption on metal gold sites only slightly. Oxidation of Au0/TiO2 by oxygen failed to produce cationic gold species. However, metallic gold was oxidized by heating the sample in a NO + O2 mixture even at 573 K.

Dates et versions

hal-03663503 , version 1 (10-05-2022)

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Tz. Venkov, Katia Fajerwerg, L. Delannoy, Hr. Klimev, K. Hadjiivanov, et al.. Effect of the activation temperature on the state of gold supported on titania: An FT-IR spectroscopic study. Applied Catalysis A : General, 2006, 301 (1), pp.106-114. ⟨10.1016/j.apcata.2005.11.019⟩. ⟨hal-03663503⟩
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