Studies On Electrochemical Properties Of Transition-Metal-Substituted Polyoxometalates And Electrodes Modified With The POMs

Adsorption is a method of dipping an electrode into the solution of electroactive species, and then naturally forming a thin film laying on the electrode. The electroactive species must have a strong adsorption activity towards the electrode matrix. Adsorption is a modifying technique of simplicity and stability. Sol-gel technique is a process by polycondensation of hydrolyzed metal alkyl compound in acidic condition in presence of the hybrid electroactive species at ambient temperaturesto form tri-dimension porous matrix. The electroactive species is doped in the matrix. The technique has an ability of regulation the physical and chemical character of porous materials. And the material prepared by the process has a homogeneous structure. As an encapsulation method, the reagent is physically trapped with a porous matrix, it is simple and compatible with many other reagents. In the future, it will be used widely. (Bu4N)5[(CpZr)SiMo11O39] is a heteropolymolybdate that is insoluble in water. In the acidic acetonitrile solution, the heteropolymolybdate exhibit three consecutive redox processes. Every process corresponds to two overlapping single-electron transfers. The heteropolymolybdate can be adsorbed onto Au electrode surface to prepare a modified electrode. In the acidic solution, the modified electrode exhibits the same electron transfer process as in acidic acetonitrile solution, and it processes the electrocatalytic activity towards the reduction of IO3-. The metrical sensitivity is so high that the modified...