Photochemical water splitting mediated by a C1 shuttle

The possibility of performing photochemical water splitting in a two-stage system, separately releasing the H and O components, has been probed with two separate catalysts and in combination with a formaldehyde/formate shuttling redox couple. In the first stage, formaldehyde releases hydrogen vigorously in the presence of an Na [Fe(CN) ]·10H O catalyst, selectively affording the formate anion. In the second stage, the formate anion is hydro-genated back to formaldehyde by water and in the presence of a Bi WO photocatalyst whilst releasing oxygen. Both stages operate at room temperature and under visible light irradiation. The two separate photocatalysts are compatible since water splitting can also be obtained in one-pot experiments with simultaneous H /O evolution.