Abstract
Powders of xercigel gamma-Al2O3 doped with various concentrations of Cr3+ and Cu2+ (M/M + Al molar fraction = 0.75-10%) were prepared via a sol-gel method. Cr3+ and Cu2+. precursors (acetylacetonate, nitrate or chloride) were added to 0.12 M 2-propanol solution of aluminum tri-sec-butoxide (ASB) and hydrolysis was performed using a H2O/ASB molar ratio of 4.7. The effect of the dopant precursor on structural, textural and morphological properties was studied. Employing acac precursors resulted in unique properties after calcination at 500 degrees C including high surface areas, as high as 455 m(2)/g, homogeneous mesopores, 3-12 nm, and amorphous powders (5-10 nm particles in diameter). On the other hand, the acac precursor enhanced the resistance to sintering mainly at higher metal loads (10%) and elevated temperature (800 degrees C). Nevertheless, the solids issued from nitrate and chloride precursors exhibited lower surface areas at high metal loads, and lower resistance to sintering. (C) 2013 Elsevier Ltd. All rights reserved.