Development of 3-methoxyaniline sensor probe based on thin Ag2O@La2O3 nanosheets for environmental safety

Abstract

Herein, a facile wet chemical method was used to synthesize doped semiconductor Ag₂O@La₂O₃ nanosheets (NSs) in an alkaline medium. Characterization tools such as ultraviolet/visible spectroscopy (UV/vis), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) in addition to field emission scanning electron microscopy (FESEM) equipped with X-ray energy-dispersive spectroscopy (EDS) were used for the optical, elemental, morphological, and structural characterizations of Ag₂O@La₂O₃ NSs. A glassy carbon electrode (GCE) was modified by the fabrication of a thin layer of Ag₂O@La₂O₃ NSs with 5% ethanolic Nafion as a conducting binder onto its flat surface for the development of a selective as well as ultra-sensitive 3-methoxyaniline (3-MA) electrochemical sensor. A simple electrochemical technique was used for the first time to detect 3-MA via an electrochemical approach using newly designed Ag₂O@La₂O₃ NSs/Nafion/GCE as a selective 3-MA electrochemical sensor in an aqueous system. Thus, electrochemical responses along with higher sensitivity, a large dynamic range and long-term stability towards 3-MA were observed by this electrochemical approach. The calibration curve was found to be linear over a wide linear dynamic range (LDR) of 3-MA concentrations (0.1 nM to 0.1 mM). The limit of detection (LOD) at a signal-to-noise ratio of 3 (S/N = 3), limit of quantification (LOQ) and sensitivity were found to be 0.085 ± 0.002 nM, 0.28 ± 0.02 nM and 0.0110 μA μM⁻¹ cm⁻², respectively, from the gradient of the calibration plot. Hence, this is a new and well-organized way for the development of a 3-MA electrochemical sensor based on Ag₂O@La₂O₃ NS-modified GCE, and it can be applied in real sample analysis for the safety of the natural environment. To the best of our knowledge, this report is the first study on the development of a highly sensitive 3-MA sensor based on Ag₂O@La₂O₃ NSs/Nafion/GCE using a reliable electrochemical technique.