Selective Amine Oxidation Using Nb₂O₅ Photocatalyst and O₂

Niobium oxide (Nb2O5) can function as a photocatalyst for selective oxidation of benzylamine rather than other semiconductor metal oxides such as TiO2, ZnO, and WO3. Various amines including primary, secondary, and cyclic amines are also photocatalytically converted to corresponding imines in excellent yields by using Nb2O5 in an atmospheric pressure of O2. Nb2O5 exhibits a catalytic activity with high selectivity even under visible light (λ > 390 nm) irradiation, although Nb2O5 does not absorb visible light.