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 H2O2 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 H2O2 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 H2O2 reduction from 1.0 to 1100 mu M with limit of detection 0.02 +/- 0.01 mu M. The higher sensitivity and selectivity as well as long-time stability and excellent reproducibility obtained, indicating the proposed sensor is an effective H2O2 based sensor. In addition, the analytical application of the nancomposite sensor was successfully examined for the determination of H2O2 in the real sample of human urine indicating that the appreciable practicality of the nonenzymatic sensor for the determination of H2O2 in physiological fluids.