Porous coralloid Polyaniline/SnO2-based enzyme-free sensor for sensitive and selective detection of nitrite

A porous coralloid nanocomposite termed as Polyaniline/tin dioxide (PANI/SnO 2 ) is designed based on the p-n junction and prepared by a method of an in-situ chemical polymerization, which is constructed as an enzyme-free sensor for nitrite (NO 2 − ) in aqueous solution. The structure and morphology of the proposed nanocomposite has been characterized by Fourier transform infrared (FTIR), X-ray powder diffraction (XRD), field emission scanning electron microscopic (FE-SEM) and transmission electron microscopy (TEM) respectively, showing it interconnects with coralloid morphology with the size of about 31–46 nm in diameter and 111–200 nm in length. A series of electrochemical studies reveal that the porous coralloid PANI/SnO 2 exhibits an excellent electrochemical performance towards the oxidation of NO 2 − and has acceptable linear response concentration range from 0.12 μM to 7.8 mM to NO 2 − oxidation, with lower detection limit of 0.04 μM (signal-to-noise ratio is 3, S/N = 3) and higher sensitivity of 121.2 μA mM −1  cm −2 . These results imply that PANI/SnO 2 may be a potential candidate for developing electrochemical sensors to detect NO 2 − in aqueous solution.