Application of ammonia intermittent temperature-programmed desorption to evaluate surface acidity of tungsten oxide supported on activated carbon

Intermittent temperature-programmed desorption of ammonia was used to study the strength and population of surface acid sites of tungsten oxide supported on activated carbon pretreated at 350 and 700 °C. Catalysts pretreated at 350 °C showed two types of surface acid sites and desorption occurred with free readsorption until a temperature of around 300 °C was reached. Pretreatment at 700 °C produced three different states of ammonia adsorbed on the catalysts and desorption occurred with free readsorption.