Electrochemical behavior of vanadium-substituted Keggin-type polyoxometalates in aqueous solution

摘要: Cyclic voltammetry was carried out on selected vanadium-substituted Keggin polyoxometalates in aqueous solution with a focus K3H2[α-SiVW11O40] · 6H2O (SiVW11O40) and K4H2[γ(1, 2)-SiV2W10O40] 4H2O (SiV2W10O40). The redox waves of the V-O W-O framework for both polyanions are pH- scan rate-dependent. first vanadium-centered wave (V-wave) SiVW11O40 shows classical potential shift as function acidity at pH < 3.5, then becomes pH-independent above this value. Above W-centers SiV2W10O40 exhibit efficient electrocatalytic activity towards reduction nitrite hydrogen peroxide while V-waves also an response nitrite-containing solutions.