TY - JOUR
T1 - Synthesis and characterization of Fe/CeO2 catalysts
T2 - Epoxidation of cyclohexene
AU - Reddy, A. Satyanarayana
AU - Chen, Chien Yen
AU - Chen, Chien Cheng
AU - Chien, Shu Hua
AU - Lin, Chin Jung
AU - Lin, Kao Hung
AU - Chen, Chih Lei
AU - Chang, Shiuan Chih
PY - 2010/3/1
Y1 - 2010/3/1
N2 - Oxidation of cyclohexene using aqueous hydrogen peroxide (30%, v/v) over iron-cerium oxide (x%Fe/CeO2; x = 0, 2, 5, 10 and 20 mol%) prepared by co-precipitation was conducted in this study in order to assess the performance of the catalysts of varying composition, and catalytic activity and product selectivity were found to strongly depend on catalyst composition, acidity and reducibility. The effects of varying the catalyst composition, reaction temperature and solvent were investigated. Cyclohexene epoxide and 1,2-cyclohexanediol were found to be the main reaction products, along with small amounts of other oxygenated products. A high cyclohexene conversion rate of 99 mol% and an epoxide selectivity of 98 mol% were observed over 5%Fe/CeO2 at 100 °C. The catalysts were characterized using various techniques and measures, including BET surface area, XRD, DRS UV-vis, potentiometric titration for acidity measurement, and XPS. XRD showed the formation of iron-cerium oxide solid solutions with cerianite cubic structures for all catalysts except FC4, and the DRS UV-vis results further indicated the formation of solid solutions. Analysis of Raman spectra revealed the presence of aggregate iron oxide species in case of 20%Fe/CeO2 catalyst. TPR revealed enhancement of the reducibility of the ceria upon Fe doping, and the potentiometric titration results showed an increase in the number of acidic sites with increasing iron content up to 5% and a decrease thereafter. TPR and XPS analyses revealed the presence of highly dispersed Fe species in the 2%Fe/CeO2 and 5%Fe/CeO2 samples, whereas for the 10%Fe/CeO2 and 20%Fe/CeO2 catalysts, aggregates of Fe species were observed. Catalytic activity was found to be correlated with the composition and acidic properties of the catalyst.
AB - Oxidation of cyclohexene using aqueous hydrogen peroxide (30%, v/v) over iron-cerium oxide (x%Fe/CeO2; x = 0, 2, 5, 10 and 20 mol%) prepared by co-precipitation was conducted in this study in order to assess the performance of the catalysts of varying composition, and catalytic activity and product selectivity were found to strongly depend on catalyst composition, acidity and reducibility. The effects of varying the catalyst composition, reaction temperature and solvent were investigated. Cyclohexene epoxide and 1,2-cyclohexanediol were found to be the main reaction products, along with small amounts of other oxygenated products. A high cyclohexene conversion rate of 99 mol% and an epoxide selectivity of 98 mol% were observed over 5%Fe/CeO2 at 100 °C. The catalysts were characterized using various techniques and measures, including BET surface area, XRD, DRS UV-vis, potentiometric titration for acidity measurement, and XPS. XRD showed the formation of iron-cerium oxide solid solutions with cerianite cubic structures for all catalysts except FC4, and the DRS UV-vis results further indicated the formation of solid solutions. Analysis of Raman spectra revealed the presence of aggregate iron oxide species in case of 20%Fe/CeO2 catalyst. TPR revealed enhancement of the reducibility of the ceria upon Fe doping, and the potentiometric titration results showed an increase in the number of acidic sites with increasing iron content up to 5% and a decrease thereafter. TPR and XPS analyses revealed the presence of highly dispersed Fe species in the 2%Fe/CeO2 and 5%Fe/CeO2 samples, whereas for the 10%Fe/CeO2 and 20%Fe/CeO2 catalysts, aggregates of Fe species were observed. Catalytic activity was found to be correlated with the composition and acidic properties of the catalyst.
UR - https://www.scopus.com/pages/publications/74149089910
UR - https://www.scopus.com/pages/publications/74149089910#tab=citedBy
U2 - 10.1016/j.molcata.2009.11.008
DO - 10.1016/j.molcata.2009.11.008
M3 - Article
AN - SCOPUS:74149089910
SN - 1381-1169
VL - 318
SP - 60
EP - 67
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
IS - 1-2
ER -