Two new inorganic-organic hybrids based on Keggin polyoxometalate and methylene blue and application in chemically bulk-modified electrode

摘要

Two new inorganic-organic hybrids based on Keggin polyoxometalate and methylene blue (MB), [C_(16)H_(18)N_3S]_4[PMo_(12)O_(40)]·2DMF·H_2O (1) and [C_(16)H_(18)N_3S]_4[GeMo_(12)O_(40)]·2DMF·H_2O (2), were synthesized and characterized. X-ray diffraction analysis shows that the organic layers composed of the parallel MB cations and the inorganic layers of discrete Keggin polyoxoanions are alternatively arranged, and UV-vis diffuse reflectance spectra in the solid state indicate the presence of new bands attributed to charge-transfer transitions between the organic dye donors and polyoxometalate acceptors. The two charge-transfer salts 1-2 were used as a solid bulk modifier to fabricate a three-dimensional bulk-modified carbon paste electrode (1 -CPE and 2-CPE). The results show that both 1 -CPE and 2-CPE present stability and have good electrocatalytic activities toward the reduction of chlorate, bromate and nitrite.