H2O2 electrochemical sensing properties of size-tunable triangular Ag nanoplates

In this paper, we investigate the hydrogen peroxide (H2O2) sensing characteristics of shape-tunable triangular Ag nanoplates (NPT) thin films. To fabricate the electrochemical sensor, the Ag NPT colloidal solutions, synthesized using the seed-mediated growth method, were deposited by drop casting onto commercial screen printed carbon electrodes (SPCE). The developed sensor showed good performances for the electro-reduction of H2O2, selected as a model analyte of reactive oxygen species (ROS) involved in the regulation of metabolic/inflammatory diseases. The electroanalytical behavior of the various Ag modified-electrodes in the presence of H2O2 has been studied by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). LSV data show a sensor sensitivity of 0.046 mu A/mu M for H2O2 concentrations lower than 100 mu M, and of 0.0085 mu A/mu M for higher concentrations up to 1 mM of H2O2. The electrochemical sensing response to this analyte has been correlated with the Ag NPT aspect ratio and Surface Plasmon Resonance (SPR) peak position, changing from 3 up to 18 and from 485 to 900 nm, respectively. We have observed that the plasmon-enhanced hydrogen peroxide reduction reaction leads to a kinetic improvement and the improved sensitivity is wavelength-dependent. The reported results suggest that these Ag-based nanomaterials can play a key role in the production of disposable, portable and on-site devices for the detection of H2O2.