Hydrogenation of crotonaldehyde on different Au/CeO2 catalysts

The gas-phase hydrogenation of crotonaldehyde was carried out at 120, 150, and 180 degrees C over An catalysts supported on ceria with low and medium surface areas (150 and 80 m(2) g(-1), respectively). An initial deactivation period was observed, followed by a steady-state regime. Ethanol was the main product in the deactivation period, whereas crotyl alcohol, butanal, butanol, and condensation products were produced under steady-state conditions. The activity and selectivity to crotyl alcohol (in the 20-32% range) were lower than those for the high-surface area ceria catalysts studied previously [B. Campo, M. Volpe, S. Ivanova, R. Touroude, J. Catal. 242 (2006) 162]. Samples were characterized by TPR, XPS, TEM, and XRD. The analysis of catalytic and characterization results indicates that gold particles supported on low- and medium-surface area ceria were relatively large, and the promotional effect of Ce3+ species was not achieved for the corresponding catalysts. Moreover, under reductive conditions, sintering still increased gold particle size. (c) 2007 Elsevier Inc. All rights reserved.