Palladium Nanoclusters Uniformly Enveloped Electrochemically Activated Graphene for Highly Sensitive Hydrogen Peroxide Sensor

Abstract Nonenzymatic sensors based on a metals nanocomposite with high sensitivity, selectivity, and stability has been received considerable interest. In this study, a novel electrochemical nanocomposite sensor based on palladium nanoclusters (PdNCs) decorated electrochemically activated graphene (EAGr) was established for highly sensitive nonenzymatic H 2 O 2 sensor. The PdNCs/EAGr nanocomposite was fabricated via an electrochemical activation of Gr by the potential cycling in the range of +0.6 to −1.8 V, followed by the electrodeposition of PdNCs at −0.4 V applied potential. The homogeneous dispersion of PdNCs/EAGr nanocomposite were characterized by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The PdNCs/EAGr nanocomposite electrode showed higher electrocatalytic activity towards the reduction of H 2 O 2 in pH 7.0 of 0.1 M PBS by significantly enhancing the reduction peak current and reduced the reduction overpotential as well as eliminated other interfering species responses. The PdNCs/EAGr electrode displayed a wide linear range for H 2 O 2 reduction from 1.0 to 1100 μM with limit of detection 0.02±0.01 μM. The higher sensitivity and selectivity as well as long‐time stability and excellent reproducibility obtained, indicating the proposed sensor is an effective H 2 O 2 based sensor. In addition, the analytical application of the nancomposite sensor was successfully examined for the determination of H 2 O 2 in the real sample of human urine indicating that the appreciable practicality of the nonenzymatic sensor for the determination of H 2 O 2 in physiological fluids.