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In this paper, well-crystalline Ag2O/ZnO and ZnO/Ag2O nanocomposites were prepared by a facile chemical method. Structural, morphological and optical properties of the nanocomposite were studied using various advanced characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), UV-Visible (UV-Vis) and photoluminescence (PL) spectroscopy. The Ag2O and ZnO were clearly identified in the composite from SEM and TEM. Significant shifting observed in the both UV-Vis and PL spectroscopy. In addition, electrocatalytic activity of the Ag2O/ZnO and ZnO/Ag2O nanocomposites studied by an electrochemical workstation. The ZnO/Ag2O nanocomposites showed better optical and electrochemical properties due to decorating the low-band gap Ag2O on the surface of hexagonal structure ZnO nanoparticles. © 2022, S.C. Virtual Company of Phisics S.R.L. All rights reserved.

Development of novel electrode materials for sensing water pollutant like nitrite, nitrate, paramedical pollutants and fertilizers is a more promising research area in electrochemical sensor field. Various pure as well as doped metal oxides were used as electrodes for sensing the water pollutants but, deficits in stability, reproducibility and real time analysis. In the present work, a promising Sn-doped CeO2 based sensor was fabricated for sensing nitrite in water. A selective concentration of Sn (5%) doped CeO2 nanoparticles were synthesized by facile chemical precipitation method. The structural, optical and morphological information were studied using various techniques. The morphological of the sample was revealed an agglomerated with spherical nanoparticles with size of 8.5 nm. The synergistic effect of Sn-CeO2/GCE improves the electrochemical behavior of nitrite on the modified surface. Sn-doped CeO2 nanoparticles has a better surface property and provides a more fine-grained media to facilitate electron transfer during the reaction between analyte and electrode. The Sn-CeO2/GCE electrode possesses excellent electrocatalytic oxidation of nitrite (NO2–) which was investigated by cyclic voltammetry (CV) and amperometry techniques. The remarkable sensitivities of nitrite were found that 245.4 µA cm−2 mM−1 and 89.53 µA cm−2 mM−1 with R2 = 0.999 and RSD of ∼ 6%. Similarly, the limit of detection (LOD) towards nitrite ion sensing was found to be 16 nM. The real time application of Sn-CeO2/GCE sensor was demonstrated by the detection of nitrite present in environmental water samples with excellent recoveries. Hence, Sn-doped CeO2 modified electrode also demonstrates good reproducibility, long time stability, and excellent selectivity properties. Thus, a developed electrochemical sensor possesses a novel promise for the construction of simple and sensitive nitrite analytical stage. © 2021 Elsevier B.V.