Modification Effect of Organic Dyes on Photocatalytic Water Splitting Activity of KTa(Zr)O3

Effects of dye modification on photocatalytic water splitting were investigated using Zr-doped potassium tantalate (KTa(Zr)O3). Various types of organic dyes, xanthenes, triphenylmethanes, carotenoids and polycyclic aromatic hydrocarbon, were investigated as modification dye. Among them, rhodamine 6G effectively improved the H2 and O2 formation rate of photocatalytic water splitting on KTa(Zr)O3. It was found that the organic dye, which has a lowest unoccupied molecular orbital (LUMO) energy level at -0.9 V vs. NHE, shows a positive effect on the photocatalytic activity, suggesting that the suitable electron orbital level exists for charge transfer from KTaO3 to organic dye followed by Pt cocatalyst.