Synthesis, characterization and electrochemical applications of Ir@SiO2 composite microspheres.

Ir nanoparticles have been synthesized by using a sample hydrothermal method while well dispersed Ir@SiO 2 composite microspheres could be obtained hydrothermally after adding SiO 2 microspheres into the synthesis system. Particles of Ir formed on the surface of SiO 2 microspheres were well crystalline similar to the pure Ir nanoparticles. Both the glassy carbon electrodes modified by Ir nanoparticles and Ir@SiO 2 composite microspheres showed weak electrochemical activities toward oxidation of dopamine and ascorbic acid. However, the Ir nanoparticles modified gold electrode displayed an obvious catalytic activity toward electrooxidation of either dopamine or ascorbic acid. For the gold electrode modified with Ir@SiO 2 composite microspheres, the electrochemical behavior could be affected obviously by the quantity of the electrocatalyst on the surface of bare gold electrode. The relationship between structure and property of both samples have been studied and analyzed based on the experimental data. [ABSTRACT FROM AUTHOR]