Sensitive determination of nitrite by using an electrode modified with hierarchical three-dimensional tungsten disulfide and reduced graphene oxide aerogel

Nanosheets of tungsten disulfide (WS2) were used to improve the physicochemical properties of reduced graphene oxide aerogel (rGA). The nanosheets were directly integrated into 3D hybrid architecture of rGA by a solvothermal mixing method by which the WS2 sheets were assembled onto the conductive graphene network. WS2 with highly exfoliated and defect-rich structure made the WS2/rGA composite possess plentiful active sites, and this enhanced the electrocatalytic capability of the composite. The introduction of poorly conductive WS2 into 3D rGA system decreases the background current of rGA when used as electrode material. This is advantageous in terms of signal to-noise ratio and analytical performance in general. The WS2/rGA electrode, best operated at a potential of 0.68V (vs. SCE) has a linear response in the 0.01 to 130M nitrite concentration range with a low detection limit of 3nM (at S/N=3). It is selective, reproducible, stable and is successfully applied to the determination of nitrite in spiked bacon samples.