Photocatalytic overall water splitting under visible light over an In–Ni–Ta–O–N solid solution without an additional cocatalyst

•A series of partially nitrided solid solutions have been synthesized.•Energy band engineering was used to tune the band configurations.•The nitrogen oxide split water under visible light with high activity.•The catalysts are stable under visible light during 10 h of reaction.

A sort of mixed nitrogen oxides, with a general formula In–Ni–Ta–O–N, has been synthesized with a solid state reaction method and used as the catalyst for visible light (λ > 400 nm) driven overall water splitting without the extra loading of a cocatalyst. Hydrogen and oxygen are evolved with a high rate in an ideal ratio of 2 to 1. The non-nitrided mixed oxide and individual oxide or nitride do not show any activity under the same reaction conditions. The elemental ratio plays a key role and the composition with the best activity is found as In:Ni:Ta:O:N = 0.9:0.1:1:3.21:0.774, with which the sample has an absorption edge at 550 nm.

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