Niobate Photocatalysts Research Articles

Photocatalytic decomposition of water over cesium-loaded potassium niobate photocatalysts

Hydrogen evolution from photocatalytic decomposition of water has been studied over cesium-loaded potassium niobate photocatalysts. Various photocatalyst supports and loading metals were used to obtain an active photocatalyst on the hydrogen evolution. The effect of additives in photoreaction as well as of the photocatalyst were also investigated. Cesium loaded on potassium niobate improved the hydrogen evolution due to its low ionization energy. The maximum rate of hydrogen evolution was about 37.4 mmol h −1 over cesium-loaded potassium niobate photocatalyst from photocatalytic decomposition of formaldehyde solution. Hydrogen evolution increased in formaldehyde solution, but oxygen evolution did not occur. Oxygen evolution increased by addition of formic acid in water. Additives enhanced the photodecomposition behavior of water and made an influence on the evolution rate of hydrogen or oxygen.

Ion exchangeable layered niobates as a noble series of photocatalysts

Some characteristic behaviors of ion-exchangeable layered niobate photocatalysts are described. The main feature of this type of photocatalysts comes from the intercalation of the reactant and the reaction proceeding at the interlayer space. In this point of view, these catalysts are regarded as “two dimensional” photocatalysts. Judging from the wide variety of these families including not only niobates but also other early transition metal oxides such as titanate, and also their unique structures, ion-exchangeable layered oxides will be an interesting subject to be used in the field of photocatalysis.

Photodecomposition of water and hydrogen evolution from aqueous methanol solution over novel niobate photocatalysts

The photocatalytic hydrogen evolution from aqueous methanol solution over K4Nb6O17 and the photodecomposition of water into H2 and O2 over NiO–K4Nb6O17 powder are described.