Bifunctional electro-catalysts based on the Keggin/Dawson-type polyoxotungstates and Cu-tris(imidazolyl) complexes

Abstract

Three new inorganic-organic hybrid compounds based on the Keggin/Dawson POMs, [Cu2(Htib)2 (α-SiW12O40)] (1), [Cu2(Htib)2(H2tib)2 (H2O)4(α-HBW12O40)2]·8H2O (2), and [Cu2(H2tib)4(H2O)2(α-HP2W18O62)2]·14H2O (3) (tib=1,3,5-tris(1-imidazoly) benzene), have been obtained through hydrothermal methods. X-ray structural analyses show that compounds 1–3 are constructed from Cu-tib modified Keggin/Dawson POMs. Compounds 1–3 have been employed to fabricate bulk-modified carbon paste electrode (CPE) (noted as n-CPEs, n=1–3) to study their electrochemical properties. Cyclic voltammetries of n-CPEs (n=1–3) display bifunctional electrocatalytic activities toward reduction of nitrite and oxidation of ascorbic acid.