Hydrogen Peroxide Electrochemical Sensor Based on Ag/Cu Bimetallic Nanoparticles Modified on Polypyrrole

Due to the strong oxidizing properties of H₂O₂, excessive discharge of H₂O₂ will cause great harm to the environment. Moreover, H₂O₂ is also an energetic material used as fuel, with specific attention given to its safety. Therefore, it is of great importance to explore and prepare good sensitive materials for the detection of H₂O₂ with a low detection limit and high selectivity. In this work, a kind of hydrogen peroxide electrochemical sensor has been fabricated. That is, polypyrrole (PPy) has been electropolymerized on the glass carbon electrode (GCE), and then Ag and Cu nanoparticles are modified together on the surface of polypyrrole by electrodeposition. SEM analysis shows that Cu and Ag nanoparticles are uniformly deposited on the surface of PPy. Electrochemical characterization results display that the sensor has a good response to H₂O₂ with two linear intervals. The first linear range is 0.1-1 mM (R² = 0.9978, S = 265.06 μA/ (mM × cm²)), and the detection limit is 0.027 μM (S/N = 3). The second linear range is 1-35 mM (R² = 0.9969, 445.78 μA/ (mM × cm²)), corresponding to 0.063 μM of detection limit (S/N = 3). The sensor reveals good reproducibility (σ = 2.104), repeatability (σ = 2.027), anti-interference, and stability. The recoveries of the electrode are 99.84-103.00% (for 0.1-1 mM of linear range) and 98.65-104.80% (for 1-35 mM linear range). Furthermore, the costs of the hydrogen peroxide electrochemical sensor proposed in this work are reduced largely by using non-precious metals without degradation of the sensing performance of H₂O₂. This study provides a facile way to develop nanocomposite electrochemical sensors.