Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The effects of hydration and reduction of V₂O₅/Al₂O₃ catalyst (14.7% V₂O₅) on ammonia adsorption have been studied by infrared spectroscopy. Both the oxidation-reduction state of the catalyst and the degree of surface dehydration have an influence on the proportions of Broensted and Lewis acidic adsorption sites in the surface. For adsorption at room temperature, the proportion of ammonia bound to Broensted acidic sites in the form of NH₄⁺ is highest with oxidized and weakly dehydrated catalyst surfaces, decreasing as the degree of reduction and dehydration temperature are increased. Negligible proportion of this form is present on strongly reduced catalyst dehydrated at 763 K.