Laboratory experiments were carried out on illuminated TiO/sub 2/-electrodes to examine the possibility of conversion and storage of solar radiation in a chemical system especially as hydrogen from the photolysis of water. Methods of preparation of new photosensitive semiconducting electrodes were studied. For the preparation of the electrodes various technique of vapour deposition and surface treatment including ion implantation were employed. The thin-layered electrodes were characterized by absorption spectroscopy and by electrochemical methods. The results of the investigations are published in 29 original contributions quoted as references and in 3 PhD thesis of co-workers. Using solar radiation only small yields of hydrogen were obtained in the photolysis of water on TiO/sub 2/ electrodes. Nevertheless it is concluded that photoelectrochemistry possesses a high potential in photocatalysis and in investigations of photooxidation processes occurring in the atmosphere. (orig.) With 36 refs., 2 tabs., 56 figs.