Single-crystalline MoO₃/functionalized multiwalled carbon nanotube nanocomposites for sensing phenothiazine in biological samples

The increasing use of pharmaceutical medications has significantly negative repercussions on the environment and human health. Here, a hydrothermal technique was employed to generate a single-crystalline molybdenum trioxide (MoO₃)/functionalized multi-walled carbon nanotubes (MoO₃/f-MWCNTs) nanocomposite that was then used as a novel electrode material for the electrochemical detection of phenothiazine (PTZ). The encapsulation of hydrothermal synthesized MoO₃ nanorods on f-MWCNTs was achieved by the sonochemical method. Extensive characterization of the MoO₃/f-MWCNTs nanocomposite is reported by means of spectroscopic and microscopic techniques. The electrode modified with the MoO₃/f-MWCNTs nanocomposite displays superior electrocatalytic activity and lower oxidation overpotential (0.492 V vs.Ag/AgCl) to PTZ compared to benchmarking electrodes modified with MoO₃ and f-MWCNTs, respectively. Electrodes performance is evaluated by means of differential pulse voltammetry that reveals a low detection limit (7 nM), more comprehensive linear response range (up to 226 µM), and superior sensitivity (2.04 µA µM⁻¹ cm⁻²). The MoO₃/f-MWCNTs nanocomposite electrode can also detect PTZ in the presence of several biological compounds and metal ions in various aqueous environments demonstrating the sensing practicality.