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. (C) 1998 Elsevier Science B.V.