Abstract
Gold nanoparticles supported on gamma-alumina and magnesia-doped gamma-alumina were synthesized by co-precipitation via a modified sol-gel method. The syntheses were found to produce catalysts with controllable acidity: the presence of either gold or magnesia produced catalyst possessing unbalanced density of acidic and basic sites, while the addition of both gold and magnesia produced catalyst possessing balanced density of relatively stronger acidic and basic sites. The variation of the acid-base strengths of the synthesized catalysts was assessed by using NH3-TPD. CO2-TPD, and infrared analysis of adsorbed CO2 and correlated to their catalytic activity in 2-propanol decomposition probe reaction. Catalysts containing magnesia and gold were found to exhibit base catalytic properties through their greater selectivity for acetone formation, while plane gamma-alumina and gamma-alumina doped with magnesia or gold exhibited acid catalytic properties through their selectivity for propene formation. (C) 2012 Elsevier B.V. All rights reserved.