Patent ID: 7271334
Filing Date: 2007-09-18
Classification: B01J,C25B,H01G,H01M,Y02E,Y02P

Abstract:
1. A system for the direct cleavage of water into hydrogen and oxygen using visible light, the system comprising a tandem cell consisting of two superimposed and electrically connected photoelectrochemical cells; a photoactive material present in a top compartment of the top cell being a film or an arrangement of layers of films of iron oxide deposited on a conducting glass and placed in contact with an aqueous electrolyte solution; said oxide comprising an n-dopant, a p-dopant, a mix of n-dopants or a mix of p-dopants and absorbing a blue and a green part of the solar emission spectrum to generate oxygen and protons from water and transmitting a yellow and a red part of the solar emission spectrum to a bottom photoelectrochemical cell, mounted, in the direction of the light, behind the top cell and comprising a dye sensitized photovoltaic film; said bottom cell converting the yellow, red and near infrared portion of the light in particular sunlight, to drive the reduction of the protons, produced in the top cell during the water oxidation process, said reduction of protons to hydrogen gas taking place in an electrolyte compartment mounted behind the bottom cell and being separated from the top cell compartment where oxygen is evolved by a glass frit or an ion conducting membrane.