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

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.