Electrochemical sensor based on porous silicon/silver nanocomposite for the determination of hydrogen peroxide

In this work, a porous silicon/silver nanocomposite was prepared and used as a modifier in carbon paste electrode, as an electrochemical sensor for the determination of hydrogen peroxide (H2O2). By using a simple and fast galvanic replacement reaction between Si atoms in the porous silicon and silver cation in aqueous HF solution, silver nanoparticles were decorated on the porous silicon without using any reducing agent. This novel nanocomposite was characterized by means of X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and cyclic voltammetry. The modified carbon paste electrode was used to study the reduction of H2O2 in 0.1 mol L−1 phosphate buffer solution (pH 7.0). Moreover, chronoamperometery was used for determination of H2O2 at the applied potential of −0.45 V (vs. Ag/AgCl). The sensor has a linear response range of 1.65 μmol L−1–0.5 mmol L−1 with a detection limit of 0.45 μmol L−1 H2O2. The electrochemical sensor showed fast and selective responses to H2O2 concentration. The applicability of the sensor was checked using real samples with satisfactory results.