Hydrothermally fabricated Syzygium polyanthum-assisted Ce-doped SnO2 nanocomposite for high-performance electrochemical nitrite sensing in environmental water samples.

In this work, a hydrothermally prepared cerium doped tin oxide (Ce-doped SnO2) was utilised to develop a sensitive electrochemical sensor for the detection of nitrite (NO2-) in real water samples. Prepared nanomaterials were studied by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-DRS), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), and ensured the successful formation of Ce-doped SnO2 and favourable characteristics of the nanocomposite for sensing of nitrite. The XRD results revealed the crystalline nature, FTIR spectra showed the existence Sn-O-Sn and/or Ce-O, TEM images show spherical morphology and has 5.40 nm of average particle size and XPS exhibited the existence of Sn, Ce, O, and C elements, confirming successful Ce incorporation onto the SnO2 structure. Electrochemical analysis by cyclic voltammetry (CV) revealed a high sensitivity (0.199 μA μM-1 cm-2). The sensor exhibited well linearity in the selected concentration range from 19 μM to 10 mM and the limit of detection (LOD) of 0.67 μM and LOQ of 6.682 μM for Ce-doped SnO2. Moreover, the Ce-doped SnO2 nanocomposite-based sensor showed high sensitivity as well as good anti-interference, stability and reproducibility performance. The sensor's effectiveness was tested in river and tap water samples through the standard addition approach and outcomes exhibited the recovery percentage (%) of 101.18% (RSD=3.02%) and 101.68% (RSD=2.66%) in river and tap water samples, respectively. The results showed the potential of the Ce-doped SnO2/GCE as an effective sensor for nitrite in real water samples.