High nuclearity Ni/Co polyoxometalates and colloidal TiO 2 assemblies as efficient multielectron photocatalysts under visible or sunlight irradiation

Visible or sunlight irradiation of high nuclearity cobalt- or nickel-centers containing polyoxometalates (POMs), alone or in association with colloidal TiO2, results in their neat, apparently direct, multielectron reduction. These materials prove very effective in the first example of visible or sunlight driven POM-based degradation of Acid Orange 7.