no single chemical compound meets all the requirements for catalytic electrodes to be used in photoelectrolysis. three different approaches toward the development of materials for such electrodes have been investigated. composite structures have been prepared by depositing sputtered cdse-srtio sub 3 and cdse-tio sub 2 films on cdse substrates; solid solutions of tio sub 2 with oxides of ta, w, nb, v and mo and of srtio sub 3 with lafeo sub 3 , srvo sub 3 and srmoo sub 3 have been prepared, primarily by ceramic techniques; and cdse and srtio sub 3 surfaces have been modified by ar-ion bombardment. these three approaches were evaluated by fabricating electrodes from materials prepared by each method and then characterizing and testing these electrodes, mainly by measuring current-voltage characteristics, spectral response and chemical stability during their operation in electrochemical cells. none of the three approaches investigated has produced efficient photoelectrolysis electrodes. one of the problems encountered in fabricating composite electrodes is that the cdse substrates cannot be heated high enough to reduce the sputtered srtio sub 3 or tio sub 2 without causing decomposition of the cdse. of the two types of composite electrodes investigated, those with cdse-tio sub 2 films have produced higher photocurrents, within an order of magnitude of those of bare cdse, but they are photoelectrochemically unstable. for some of the tio sub 2 and srtio sub 3 alloys that have been investigated the photoresponse shifts to lower energies as desired, but the magnitude of the respon