Electroactivity toward hydrogen peroxide of an aminofunctionalized silica film containing silicotungstate nanoclusters

ABSTRACT

Hydrogen peroxide (H₂O₂) is a powerful oxidizing agent used, for example, in advanced oxidative processes and glucose biosensors. Although the electroreduction reaction of H₂O₂ has been studied using polyoxometalate (POM) nanoclusters as electrocatalysts, there are not data available in the literature reporting such study using POM nanoclusters immobilizated in hybrid materials as organically modified silicate (ormosil) by sol-gel process. In this study, electrocatalytic properties of a hybrid ormosil film containing 3-aminopropyltriethoxysilane (APTS) and silicotungstic acid (HSiW), a Keggin type POM cluster, toward H₂O₂ have been evaluated. Cyclic voltammetry experiments showed that H₂O₂ was electroreduced by this hybrid ormosil film at – 0,17 V vs. Ag/AgCl in acidic medium, pH 3,0, and in the concentration range from 4,6 x 10^-4 mol L⁻¹ to 2,3 x 10⁻³ mol L⁻¹. ³¹P Nuclear Magnetic Resonance Spectrum indicated that HSiW clusters maintained their structures in the ormosil network. Fourier Transform Infrared Spectrum demonstrated that HSiW and the ormosil network interact through electrostatic interactions. These findings indicate that the hybrid ormosil with APTS and HSiW can contribute to the field of H₂O₂ recognition.

Keywords
Polyoxometalate; Sol-Gel Process; Hydrogen Peroxide; Organic-Inorganic Hybrid Film; Ormosil