Abstract: (Bu₄N)₅［(CpZr)SiMo₁₁O₃₉］ is insoluble in water and soluble in acetonitrile. In the acidic acetonitrile solution, the heteropolymolybdate exhibits three steps redox processes. By means of multifarious electroanalysis techniques， the electron transfer for the first step was explored. Every step process corresponded to two overlapping singleelectron transfers. The heteropolymolybdate was adsorbed onto Au electrode surface to prepare a modified electrode. On this electrode, the electrocatalytic reduction of IO₃^-， BrO₃^- and NO₂^- were investigated.

Key words: heteropolymolybdate, iodate, cyclic voltammetry, chronocoulometry