Anodic electrodeposition of iridium oxide particles on glassy carbon surfaces and their electrochemical/SEM/XPS characterization

摘要

In this study an electrodeposition procedure of hydrated Ir(III) and Ir(IV) oxyhydroxide species operating under anodic conditions and directly from aged alkaline solution containing 6 mM IrCla(6)(3-) and 20 mM Cl- a ligand specie was defined for the surface modification of the glassy carbon electrode substrates. Optimum efficiency of iridium oxide deposition was obtained by cycling the potentials (100 mV s(-1)) between -0.7 V and 1.0 V vs. SCE. The SEM analysis reveals that the iridium oxide is uniformly distributed on the entire electrode surface with particles having a globular form. All particles, appear isolated or in aggregated structures with an average diameter comprised between 0.03 mu m and 0.4 mu m. The XPS curve fitting analysis reveals that the surface deposit is formed of hydrated Ir(III) and Ir(IV) oxyhydroxide species. The electrocatalytic activity of the GC/IrOx electrode toward the oxidation of semicarbazide under acidic condition (i.e., 50 mM HClO4) using cyclic voltammetry and chronoamperometry, was also investigated. (C) 2014 Elsevier B.V. All rights reserved.