Photocatalytic hydrogen production using suspended photocatalysts was studied. TiO2 anatase in a powder form was used as photocatalyst. Our investigation aims towards the creation of improved photocatalysts to be used in the production of hydrogen from water or aqueous solutions of organic compounds. TiO2 anatase in a powder form was used originally as photocatalyst. It was found that the photocatalytic activity depends significantly on catalyst type and its modification such as loading with various transition metal oxides. The different operating conditions of photocatalytic hydrogen production process were studied, which include: photocatalyst type and its concentration, pH, light harvesting material type and its concentration, activated carbon concentration, electron donor material type and its concentration, and the time of photolysis. The prepared photocatalyst gave good results for the hydrogen production rate. (c) 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.