In Situ Growth of Surfactant-Free Gold Nanoparticles
on Nitrogen-Doped Graphene Quantum Dots for Electrochemical Detection
of Hydrogen Peroxide in Biological Environments
In this work, we report a green and
simple strategy for the in
situ growth of surfactant-free Au nanoparticles (Au NPs) on nitrogen-doped
graphene quantum dots (Au NPs–N-GQDs). The formation of hybrid
was achieved by just mixing the N-GQDs and HAuCl<sub>4</sub>·4H<sub>2</sub>O without addition of any other reductant and surfactant.
High-resolution transmission electron microscopy (HRTEM), X-ray diffraction
(XRD), and X-ray photoelectron spectroscopy (XPS) characterizations
clearly showed the formation of Au nanoparticles with predominantly
exposed (111) facets which can provide more adsorption sites. Such
nonsurfactant-capped Au NPs can provide naked catalytic surface with
highly electrocatalytic activity. The Au NPs–N-GQDs exhibit
high sensitivity and selectivity for electrochemical detection of
hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) with a low detection
limit of 0.12 μM and sensitivity of 186.22 μA/mM cm<sup>2</sup>. Importantly, the Au NPs–N-GQDs-based electrochemical
biosensor has shown great potential applications for detection of
H<sub>2</sub>O<sub>2</sub> levels in human serum samples and that
released from human cervical cancer cells with satisfactory results.
The present study demonstrates that such novel Au NPs–N-GQDs
nanocomposite is promising for fabrication of nonenzymatic H<sub>2</sub>O<sub>2</sub> biosensors
