TY - JOUR
T1 - Selectivity of photocatalytic oxidation of gaseous ethanol over pure and modified TiO2
AU - Vorontsov, Alexandre V.
AU - Dubovitskaya, Vera P.
N1 - Funding Information:
The support of INTAS via fellowship YSF 2002-55 is gratefully acknowledged. We acknowledge the support of RFBR through Grant 02-03-08002.
PY - 2004/1/1
Y1 - 2004/1/1
N2 - The rates of the two main stages of photocatalytic ethanol destruction - oxidation of ethanol to acetaldehyde and oxidation of acetaldehyde to CO 2 - were studied under varied concentrations of ethanol and acetaldehyde and photocatalyst irradiance, at different temperatures, and over different photocatalysts. The rates followed the semiempirical three sites Langmuir-Hinshelwood model that envisages sites for ethanol and acetaldehyde adsorption and additional sites for competitive adsorption of ethanol and acetaldehyde. The increase in irradiance gave rise to higher selectivity toward CO2 via increased concentrations of gaseous intermediate acetaldehyde. However, the rate of ethanol oxidation rose faster than the rate of acetaldehyde oxidation. The selectivity toward CO2 monotonically decreased with temperature over TiO2 and the rate of oxidation reached a maximum at 80°C. Among platinum-doped catalysts, the best activity was found for 1.1% Pt/TiO2. Platinum addition to TiO 2 resulted in a 1.5- to 2-fold increased overall rate of oxidation. The selectivity to CO2 over Pt/TiO2 catalyst monotonically increased with temperature. Separate studies in a batch reactor demonstrated that addition of platinum changed the product distribution. Acetic acid, instead of carbon monoxide, was formed in copious quantities over the Pt/TiO2 catalyst.
AB - The rates of the two main stages of photocatalytic ethanol destruction - oxidation of ethanol to acetaldehyde and oxidation of acetaldehyde to CO 2 - were studied under varied concentrations of ethanol and acetaldehyde and photocatalyst irradiance, at different temperatures, and over different photocatalysts. The rates followed the semiempirical three sites Langmuir-Hinshelwood model that envisages sites for ethanol and acetaldehyde adsorption and additional sites for competitive adsorption of ethanol and acetaldehyde. The increase in irradiance gave rise to higher selectivity toward CO2 via increased concentrations of gaseous intermediate acetaldehyde. However, the rate of ethanol oxidation rose faster than the rate of acetaldehyde oxidation. The selectivity toward CO2 monotonically decreased with temperature over TiO2 and the rate of oxidation reached a maximum at 80°C. Among platinum-doped catalysts, the best activity was found for 1.1% Pt/TiO2. Platinum addition to TiO 2 resulted in a 1.5- to 2-fold increased overall rate of oxidation. The selectivity to CO2 over Pt/TiO2 catalyst monotonically increased with temperature. Separate studies in a batch reactor demonstrated that addition of platinum changed the product distribution. Acetic acid, instead of carbon monoxide, was formed in copious quantities over the Pt/TiO2 catalyst.
KW - Irradiance
KW - Langmuir-Hinshelwood
KW - Light intensity
KW - Photocatalysis
KW - Photocatalytic activity
KW - Platinization
KW - Temperature
UR - http://www.scopus.com/inward/record.url?scp=0345714581&partnerID=8YFLogxK
U2 - 10.1016/j.jcat.2003.09.011
DO - 10.1016/j.jcat.2003.09.011
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AN - SCOPUS:0345714581
SN - 0021-9517
VL - 221
SP - 102
EP - 109
JO - Journal of Catalysis
JF - Journal of Catalysis
IS - 1
ER -