Low Melting Point and High Stability Polyoxomolybdate-based Ionic Liquids as Photocatalysts

The polyoxometalate-imidazole ionic liquids(POM-ILs) with low melting points at 94.5 and 95.5 degrees C, [C(n)mim](4)[Mo8O26](C(n)mim=1-alkyl-3-methylimidazolium, n=12,14), have been successfully synthesized and characterized by DSC, single-crystal X-ray diffraction and TGA, etc. The two POM-ILs have relatively high stability with decomposing temperature up to about 347 and 344 degrees C, respectively. Further photocatalytic performance was measured via the degradation of rhodamine B(RB) in aqueous solution. The experiments show that the conversion reached to 90% after 90 min under UV-light and the degradation efficiency depended on pH value, different dosages and so on. In addition, the catalysts can be recycled for several times without significant loss of activity.