A quantitative method of photoadsorption determination for irradiated catalyst in liquid–solid system

A method for determining the amount of substrate adsorbed onto the catalyst surface in liquid–solid photocatalytic system under reaction conditions (photoadsorption) is proposed. The method has been applied to the photocatalytic oxidation of benzyl alcohol carried out in aqueous suspensions of a home prepared TiO₂ catalyst. The influence of alcohol concentration, catalyst amount and irradiation power on photoadsorption was investigated. The photoadsorption per unit mass of catalyst increased by increasing concentration of benzyl alcohol and irradiation power but it decreased, increasing the catalyst amount. By taking into account the photoadsorption phenomena, the kinetic modeling of the photooxidation process has been carried out and the parameters of the model have been determined. The results indicate that all these parameters are favorably affected by an increase of the photon flow absorbed per unit mass of catalyst.