Stable photoelectrochemical cells for the splitting of water

Abstract

FOLLOWING Fujishima and Honda's suggestion of water photolysis by a photoelectrochemical cell¹, 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 pH 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-TiO₂ and n-SrTiO₃ and the cathodes p-CdTe and p-GaP can be combined to form four separate stable self-driven cells: n-TiO₂–p-CdTe, n-TiO₂–p-GaP, n-SrTiO₃–p-CdTe and n-SrTiO₃–p-GaP capable of water photoelectrolysis.