ADSORPTION OF HEXACHLOROPLATINIC ACID ON γ-ALUMINA COATINGS FOR PREPARATION OF MONOLITHIC STRUCTURE CATALYSTS

Abstract

The adsorption of hexachloroplatinic acid on γ-Alumina coatings is investigated in order to prepare monolithic structure catalysts for carbon monoxide oxidation. For acid concentrations in the range 0.25-1.5 mM the adsorption is examined in a batch process and a kinetic model is proposed and evaluated. The pH of the solution has a major impact on the adsorption rate and dispersion of Pt on Al₂O₃ and when acidity becomes lower than 1.5 pH value the deposition of Pt on the catalyst by pore volume impregnation is favourable. The catalytic properties of Pt-alumina as oxidation catalyst for CO depend strongly on the adsorption rate of H₂PtCI₆. A difference of 80 °C at the light off temperature is observed for catalysts prepared by adsorption from solutions with different acidity.

KEYWORDS:

• Platinum/alumina
• Adsorption
• Monolithic catalysts.

Additional information

Notes on contributors

C.J. PHILIPPOPOULOS

To whom correspondence should be addressed.