A tandem dye-sensitized photoelectrochemical cell for light driven hydrogen production

Combining a dye-sensitized photoelectrochemical cell for hydrogen production based on a SnO₂ photoanode in series with a dye-sensitized photovoltaic solar cell using a TiO₂ photoanode yields a tandem system for the generation of H₂ from hydroquinone using only light energy and no applied electrical bias. To target distinct portions of the solar spectrum, a more blue-absorbing free base porphyrin and a more red-absorbing Si phthalocyanine chromophore are used at the two photoelectrodes. With incorporation of a suitable water oxidation catalyst, a similar approach could enable tandem photochemical water splitting without the need for p-type semiconductors.