Mg. Cutrufello et al., Acid-base properties and catalytic activity of nanophase ceria-zirconia catalysts for 4-methylpentan-2-ol dehydration, PCCP PHYS C, 1(14), 1999, pp. 3369-3375
The room-temperature high energy ball-milling technique was used to prepare
nanophase Ce1-xZrxO2 (x = 0; 0.2; 0.5; 0.8; 1) catalysts. The acid-base pr
operties of these catalysts were investigated by means of adsorption microc
alorimetry, using NH3 and CO2 as probe molecules. The catalytic activity fo
r 4-methylpentan-2-ol dehydration was tested at atmospheric pressure in a f
ixed-bed flow microreactor. The inclusion of increasingly high contents of
zirconium into the ceria lattice has a complex influence on the acidity and
basicity of the pure parent oxide, in terms of both number and strength of
the sites. A maximum in 1-alkene selectivity is observed for the ceria-ric
h catalyst and a minimum for the zirconia-rich sample. Catalytic results ar
e correlated with the acid-base properties and can be interpreted in the li
ght of the mechanism formerly proposed for zirconia, ceria and lanthania. S
urface conditioning of the zirconia-rich catalyst occurs during the run, re
sulting in a remarkable variation of selectivity.