Highly efficient water splitting over K3Ta3B2O12 photocatalyst without loading cocatalyst

K3Ta3B2O12 with pillared structure showed a high photocatalytic activity for water splitting into H-2 and O-2 without assistance of cocatalysts. The bandgap of K3Ta3B2O12 was 4.2eV. K3Ta3B2O12 showed blue photolurninescence at 77K by the bandgap excitation as well as other tantalate photocatalysts for water splitting.