Bimetallic PdCu/SPCE non-enzymatic hydrogen peroxide sensors

Screen printed carbon electrodes (SPCE) were decorated with PdCu bimetallic alloys via a facile co-electrodeposition method to develop disposable non-enzymatic H₂O₂ sensors. The electrochemical performance of the biosensors was evaluated in terms of selectivity, sensitivity, and stability with a goal of demonstrating that employing a bimetallic PdCu non-enzymatic system can push forward the state of the art in hydrogen peroxide sensing. The physical characterization of the biosensors was conducted using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) techniques. Sensors consisting of PdCu bimetals showed higher sensitivity than Pd/SPCE and Cu/SPCE electrodes toward H₂O₂. The fabricated PdCu/SPCE sensors showed a sensitivity of 396.7 μA mM^-1 cm^-2, a linear range from 0.5 mM to 11 mM, and a low limit of detection (0.7 μM) at the applied potential of -0.3 V. The use of relatively low working potential eliminated the interference effect of the common electroactive species (ascorbic acid, uric acid, and glucose) present in a real sample, which are usually a concern for non-enzymatic sensing systems. In addition, the high reproducibility (RSD = 2.5%), and excellent long term stability render PdCu/SPCEs as attractive materials for the construction of disposable enzyme-free H₂O₂ sensors.