Electrochemical behavior and its electrocatalytic properties of chemically modified electrode with Keggin-type [SiNi(H2O)W11O39]6−

A monolayer of Keggin-type heteropolyanion [SiNi(H2O)W11O39]6− was fabricated by electrodepositing [SiNi(H2O)W11O39]6− on cysteamine modified gold electrode. The monolayer of [SiNi(H2O)W11O39]6− modified gold electrode was characterized by atomic force microscopy (AFM) and electrochemical method. AFM results showed the [SiNi(H2O)W11O39]6− uniformly deposited on the electrode surface and formed a porous monolayer. Cyclic voltammetry exhibited one oxidation peak and two reduction peaks in 1.0 M H2SO4 in the potential range of −0.2 to 0.7 V. The constructed electrode could exist in a large pH (0–7.6) range and showed good catalytic activity towards the reduction of bromate anion (BrO3−) and nitrite (NO2−), and oxidation of ascorbic acid (AA) in acidic solution. The well catalytic active of the electrode was ascribed to the porous structure of the [SiNi(H2O)W11O39]6− monolayer.