A sensitive electrochemical H₂O₂ sensor based on PDAG-decorated reduced graphene oxide nanocomposites

We report on the construction of PdAg/reduced graphene oxide (rGO)-based electrochemical H₂O₂ sensors by exploiting the high surface area and fast electron transfer rate of rGO, as well as the high electrocatalytic activity of palladium-silver nanoparticles. The nanocomposites were prepared via a one-step reduction method and characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), Fourier transform spectroscopy (FTIR), and X-ray diffraction (XRD) techniques. The performance of the sensors was evaluated by cyclic voltammetry and chronoamperometry methods. The SEM images showed that the constructed nanocomposites had three-dimensional structure (3D), which both provided large specific surface area for the electrochemical reactions and enhanced the transports of the analyte on the sensors surface. The PdAg/rGO sensors had a high sensitivity of 247.6 ± 2.7 μA · mM−¹ · cm⁻² and the 3D structure of rGO along with the high electrocatalytic activity of PdAg nanoparticles allowed the detection of H₂O₂ in a wide concentration range from 0.05 mM to 28 mM. To evaluate the selectivity of the sensors, the analytical response toward the exposure of H₂O₂, ascorbic acid, uric acid, and glucose were measured. The practical applicability of PdAg/rGO-based sensor design was studied in human serum.