Hexagonal cobalt oxyhydroxide nanoflakes/reduced graphene oxide for hydrogen peroxide detection in biological samples.

Abnormal concentration of hydrogen peroxide (H2 O2 ) in blood plasma and cells may lead to several diseases. Thus, it is important to develop a selective and sensitive method to monitor H2 O2 . In the present work, a novel nonenzymatic H2 O2 -sensing platform based on cobalt oxyhydroxide (CoOOH)/reduced graphene oxide (RGO) nanocomposite was fabricated. CoOOH nanoflakes were firstly synthesized via soft chemistry routes and then assembled on the surface of RGO. A series of characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy demonstrated that hexagonal CoOOH nanoflakes were well distributed on the surface of RGO. The nanocomposite exhibited excellent electrochemical performance for H2 O2 detection. Two linear ranges of 6-200 μM and 200-1500 μM were obtained, and the detection limit was 0.01 μM (signal-to-noise ratio was 3). The good performance was attributed to more exposed catalytic active sites of CoOOH nanoflakes compared with zero-dimensional nanoparticles and outstanding conductivity of RGO as well as their synergistic effect. Moreover, the nanocomposite was used to detect H2 O2 from human serum and HeLa cells with satisfactory results. Graphical abstract ᅟ.