Photocatalytic Hydrogen Production from Water Using N-Doped Ba₅Ta₄O₁₅ under Solar Irradiation

Solar light induced water splitting on photocatalysts is a very important area of research. Anion doping of photocatalysts normally active only under ultraviolet (UV) light has been reported to be a possible way of increasing visible light photocatalytic performance. Here we report a (111) layered perovskite material Ba5Ta4O15 that was doped with nitrogen. The resulting Ba5Ta4O15–xNx compound exhibited an extraordinary increase in visible light absorbance. The uniform distribution of the nitrogen dopant was attributed to the unique layered (111) structure, which provides intergallery spacings between the perovskite layers for the dopant to diffuse easily in the compound particles during the doping process. It was further verified by density of states that the N 2p states mixed with pre-existing O 2p states that moved the valence band maximum upward without effecting the conduction band, which was composed of the Ta 4d orbital. The doped photocatalysts exhibited not only increased visible light absorbance but increased photocatalytic hydrogen production of ∼50% under simulated solar irradiation, in comparison to that of undoped parent compound.

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