After UV-light irradiation for 20min, 60% of the acid red G was decoloured, which was higher than 20% of the Degussa P25 and K_4Nb_6O_17 obtained by solid-state reaction.

• 光催化降解20min后，水热法合成的K_4Nb_6O_17的脱色率已达60%25，而高温固相法的K_4Nb_6O_17和Degussa P25的脱色率都仅为20%25。