Abstract: Ionic liquid-like polyoxometalates(POM-IL), [PyPS]nH3-nPW12O40·xH2O(n=1,2,3), were synthesized by using pyridine, 1,3-propanesultone and tungstophosphoric acid as raw materials. The compounds were characterized by means of FT-IR, UV-Vis, 1H NMR and elementary analyses. The results showed that Keggin structure of POM was kept and there were character bands of pyridyl propylsulfonic acid in the POM-IL salts. All prepared compounds possess melting-points above 130 ℃ and the melting-points decreased with the increase of the organic component. Furthermore, the photocatalytic performances of these POM-IL samples for the degradation of aqueous dyes were investigated. Under UV irradiation, the samples with n=1 and 2 showed similar photocatalytic activities to that of tungstophosphoric acid for the degradation of methyl orange. Under visible light, all POM-IL salts exhibit the same photocatlytic activities which are superior to tungstophosphoric acid for the degradation of isatin. Therefore, all these POM-IL salts might be promising photocatalysts for the degradation of some dyes under visible light.

Key words: Ionic liquid, Polyoxometalates, Synthesis and characterization, Photocatalysis