Ion exchanged potassium titanoniobate as photocatalyst under visible light

Potassium titanoniobate (KTiNbO5) was synthesized by solid-state reaction. The potassium ion of KTiNbO5 was exchanged for hydrogen ion in hydrochloric acid, and the sample was heat-treated. The shrinkage of the distance between titanoniobate layers that arise from ion-exchange was observed by using X-ray diffraction. The absorption edges of the UV–Vis spectra for the ion exchanged samples which were treated at higher temperature shifted from ultraviolet region to visible region. The change of binding energy was observed by X-ray Photoelectron Spectroscopy. Photocatalytic property of the ion exchanged and subsequently heat-treated under artificial solar irradiation was less than that of the titanium dioxide. On the other hand, that of the ion-exchanged and heat-treated sample under visible irradiation was better than that of the titanium dioxide.