A wide visible light active photocatalyst Mg5Ta4O15-xNy for water oxidation and reduction

More than 1.6 eV band gap reductions have been realized on Mg 5 Ta 4 O 15 by nitrogen doping with its pseudobrookite structure maintained. The nitrogen doped Mg 5 Ta 4 O 15 , i.e. Mg 5 Ta 4 O 15-x N y , shows broad absorption in the visible light region and promising photocatalytic activity for both water reduction and oxidation reactions under visible light illumination (λ ≥ 400 nm). Apparent quantum efficiency as high as ~0.90% has been achieved at 420 ± 20 nm on Mg 5 Ta 4 O 15-x N y which is comparable to a number of active metal oxynitrides photocatalysts . Apart from visible light absorption, Nitrogen doping on Mg 5 Ta 4 O 15 is also accompanied by improved surface hydrophilicity and a negative shift of flat band potential. This simple strategy for band gap engineering can be extended to other metal oxides which may open new playgrounds in the design and development of efficient visible light active photocatalysts.