Electrochemical Properties of Ag@iron Oxide Nanocomposite for Application as Nitrate Sensor

Ag@iron oxide nanocomposite powders were synthesized via a two‐step chemical method. Characterization by UV‐Vis, XRD, SEM‐EDX and TEM revealed they are composed of nanosized crystalline silver particles in strict contact with amorphous iron oxide(s). The electrochemical behavior of the synthesized Ag@iron oxide composite was investigated by cyclic voltammetry. Compared with the single phase‐modified electrodes, the Ag@iron oxide/SPCE electrode exhibits an enhanced cathodic current in response to the target analyte, due to a synergistic effect between Ag crystallites and amorphous iron oxide nanoparticles. An amperometric sensor for detection of nitrate based on Ag@iron oxide modified screen‐printed electrode (Ag@iron oxide/SPCE) has been fabricated, showing a good sensitivity (663 µA mM −1 cm −2 ) and a detection limit of 30 µM.