Temperature-programmed desorption study of Re/γ-Al2O3 catalysts prepared from Re2(CO)10 precursor

Alumina supported rhenium catalysts were prepared by gas-phase sublimation technique from carbonyl based precursor. Temperature-programmed desorption (TPD) profiles measured at different rhenium loadings suggested the formation of a new rhenium phase when the rhenium content reached a certain level. Acidic properties of the catalysts were investigated by temperature-programmed desorption of ammonia. Total acidity of the samples increased until the metal loading reached 4.1 wt.%, and afterwards decreased. As the metal loading increased, the portion of the middle strength acid sites increased at the expense of the lower strength acid sites which dominated in the pure support sample and samples with low rhenium content. (C) 2001 Elsevier Science B.V. All rights reserved.