Silica Supported Platinum Catalysts for Total Oxidation of the Polyaromatic Hydrocarbon Naphthalene: An Investigation of Metal Loading and Calcination Temperature

A range of catalysts comprising of platinum supported on silica, prepared by an impregnation method, have been studied for the total oxidation of naphthalene, which is a representative Polycyclic Aromatic Hydrocarbon. The influence of platinum loading and calcination temperature on oxidation activity was evaluated. Increasing the platinum loading up to 2.5 wt.% increased the catalyst activity, whilst a 5.0 wt.% catalyst was slightly less active. The catalyst containing the optimum 2.5 wt.% loading was most active after calcination in air at 550 °C. Characterisation by carbon monoxide chemisorption and X-ray photoelectron spectroscopy showed that low platinum dispersion to form large platinum particles, in combination with platinum in metallic and oxidised states was important for high catalyst activity. Catalyst performance improved after initial use in repeat cycles, whilst there was slight deactivation after prolonged time-on-stream.