Preparation of polyaniline grafted graphene oxide–WO3 nanocomposite and its application as a chromium(iii) chemi-sensor

Abstract

A nanohybrid of polyaniline grafted graphene oxide@WO₃ (PANI-g-rGO@WO₃) was prepared by oxidative polymerization of aniline in the presence of tungsten oxide and reduced graphene oxide. The physicochemical characterization of PANI-g-rGO@WO₃ was done by FESEM, X-ray diffraction microscopy, FTIR, UV-Vis spectroscopy, thermogravimetric analysis and XPS. The composite was analyzed for hazardous metal selectivity and was found to be highly sensitive for trivalent chromium (Cr³⁺). For potential trivalent chromium (Cr³⁺) cation sensor development, the PANI-g-rGO@WO₃ nanocomposite was deposited on a flat silver electrode (AgE, surface area, 0.0216 cm²) with conducting binders coating to give a sensor with a fast selective response towards trivalent chromium cations in the liquid phase. The sensor also exhibits good sensitivity, long-term stability, and enhanced electrochemical responses. The calibration plot is linear (r² = 0.9815) over a 0.1 nM to 0.01 M Cr³⁺ concentration range. The sensitivity is ∼4.4251 μA mM⁻¹ cm⁻² and the detection limit is 0.031 ± 0.010 nM (signal-to-noise ratio, at a SNR of 3). The development of a sensitive sensor for hazardous and carcinogenic chromium cations is also commenced using the PANI-g-rGO@WO₃ nanocomposite and the I–V method for promising potential future applications in the environmental and healthcare fields.