Sodium-hypophosphite as a novel reducing agent in the preparation and characterization of silver/silica gel catalysts

New catalysts with different loading 2, 5, 8 and 11 (wt.%) silver on silica gel were prepared by chemical reduction method using a sodium-hypophosphite as a novel reducing agent. The catalytic activity was studied through the dehydrogenation of ethanol in a micro catalytic pulse system at 300-450 degrees C and at hydrogen flow rate 50 mL/min. The structural changes that accompanying the catalysts preparation were detected by X-ray diffraction, differential scanning calorimetry and infrared techniques. Results show that ethanol dehydrogenation was mainly dependent on the silver content and metal-support interaction. In other words, catalyst sample containing 8% Ag was found the most active and selective for acetaldchyde formation and that contain 11% Ag is rich with silver silicate in certain mode. A texture property of the prepared catalysts was investigated. (c) 2005 Elsevier B.V. All rights reserved.