(Oxy)nitrides as new photocatalysts for water splitting under visible light irradiation

A range of transition-metal oxynitrides and a nitride were examined as potential photocatalysts active under visible light. (Oxy) nitrides based on tantalum, niobium and titanium are found to absorb visible light (lambdaless than or equal to600 nm), and some of them are found to evolve H-2 or O-2 from aqueous solutions containing a sacrificial electron donor (CH3OH) or acceptor (Ag+), respectively, via band gap excitation without noticeable photo-degradation of the catalyst itself.