Catalysis of Nickel Ferrite for Photocatalytic Water Oxidation Using [Ru(bpy)3]2+ and S2O82-

Single or mixed oxides of iron and nickel have been examined as catalysts in photocatalytic water oxidation using [Ru(bpy)(3)](2+) as a photosensitizer and S2O82- as a sacrificial oxidant. The catalytic activity of nickel ferrite (NiFe2O4) is comparable to that of a catalyst containing Ir, Ru, or Co in terms of O-2 yield and O-2 evolution rate under ambient reaction conditions. NiFe2O4 also possesses robustness and ferromagnetic properties, which are beneficial for easy recovery from the solution after reaction. Water oxidation catalysis achieved by a composite of earth-abundant elements will contribute to a new approach to the design of catalysts for artificial photosynthesis.