Abstract: A kind of inorganic-organic hybrid semiconductor composite nanoparticles: Dawson-type phosphomolybdate-doped polypyrrole(P₂Mo₁₈-PPy) was designed and prepared using microemulsion oxidation-polymerization at room temperature and characterized by TEM and IR. The P₂Mo_18-PPy was used as a bulk-modifier to fabricate a chemically modified carbon paste electrode(CPE) by direct mixing, which represents the example of polyoxometalates(POMs)-doped semiconductor polymer nanoparticles modified electrode. Both the advantage of POMs-doped polymer and the surface-renewal property of the CPE were fully utilized. The electrochemical behavior of the P₂Mo_18-PPy bulk-modified CPE(P₂Mo_18-PPy-CPE) was investigated with cyclic voltammetry. Three couples of reversible redox peaks were observed in the range from +800 to 0 mV, which corresponded to the reduction and oxidation through two-, four- and six-electron processes, respectively. The P₂Mo_18-PPy-CPE showed a high electrocatalytic activity for the reduction of nitrite, which expanded the application of POMs-doped semiconductor polymer nanoparticles.

Key words: Dawson-type phosphomolybdate, Polypyrrole, Composite nanoparticles, Bulk-modified, Carbon paste electrode, Electrocatalysis