Patent ID: 7651675

Claim:
A process of producing a nitrogen-doped titanium oxide for a photocatalyst having light absorption in the visible light region, comprising the steps of: preparing a titania/organic substance composite including an organic ligand coordinated to flaky titania and forming a layered structure; immersing said titania/organic substance composite in aqueous ammonia, thereby substituting the organic ligand between layers with a hydroxyl group by a ligand exchange reaction, and at the same time, introducing ammonium in the aqueous ammonia into between layers of the titania having the layered structure; drying the resulting composite of titania and ammonium; and, after the drying step, heating the composite at a temperature in the range of 400° C. to 500° C., whereby nitrogen is doped into titania by thermal decomposition of the ammonium and, in addition, titania is crystallized to an anatase form.