Stable photoelectrochemical cells for the splitting of water

FOLLOWING Fujishima and Honda's suggestion of water photolysis by a photoelectrochemical cell 1 , no stable cell has been reported (but compare refs 2, 3) capable of water decomposition without the application of either an external bias or a p H gradient. The main problems have been to find stable anodes and cathodes with sufficiently negative and positive critical photopotentials, respectively, so that they may be suitably combined in a self-driving photo cell producing hydrogen and oxygen from water. We report here that the anodes n -TiO 2 and n -SrTiO 3 and the cathodes p -CdTe and p -GaP can be combined to form four separate stable self-driven cells: n -TiO 2 – p -CdTe, n -TiO 2 – p -GaP, n -SrTiO 3 – p -CdTe and n -SrTiO 3 – p -GaP capable of water photoelectrolysis.