Preparation and Characterization of Palladium Catalysts

There is a critical need for improved combustion-oxidation catalysts to reduce emissions of toxic volatile organic compounds (VOCs) emitted from exhaust gas of gasoline combustion in automotive vehicles. Materials and systems currently available, such as the three way catalytic converter (TWC), have low activity below 400 °C in the catalytic process. Palladium catalysts were prepared by alternative methods including: preparation by wet impregnation or incipient wetness, drying by room temperature or air-oven, and support choice between silica and alumina. These catalysts were prepared to meet the demand for low temperature oxidation. Results indicated a 5% increase in percent dispersion of metal across the support due to room temperature drying conditions, a higher surface area and crystallite size favoring alumina or silica support, a much larger monolayer uptake for alumina supported catalysts, and characteristic site strength of 600 chemisorption characterized by temperature programmed desorption (TPD)