Poly(pyrrole-<i>co-o</i>-toluidine) wrapped CoFe₂O₄/R(GO–OXSWCNTs) ternary composite material for Ga³⁺ sensing ability

In this study, we report a novel ternary conductive hybrid material with high stability, conductivity, and excellent electrochemical Ga³⁺ sensing ability. Ternary poly(pyrrole-<i>co-o</i>-toluidine)/CoFe₂O₄/reduced graphene oxide-oxidized single-wall carbon nanotube nanocomposites in the form of P(Py-<i>co</i>-OT)/CF/R(GO-OXSWCNTs) NCs have been synthesized through an <i>in situ</i> chemical polymerization method <i>via</i> a facile three-step approach. Single phase CoFe₂O₄ (CF) nanoparticles (NPs) were synthesized using an egg white method, while reduced graphene oxide-oxidized single-wall carbon nanotubes R(GO-OXSWCNTs) were prepared <i>via</i> co-reduction of graphene oxide along with oxidized SWCNTs flowed by coating CF and R(GO-OXSWCNTs) with a poly(pyrrole-<i>co-o</i>-toluidine) matrix P(Py-<i>co</i>-OT) copolymer. The results of X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR) and Raman indicated that the P(Py-<i>co</i>-OT)/CF/R(GO-OXSWCNTs) NCs were effectively synthesized with strong interactions among the constituents. The thermal stability of P(Py-<i>co</i>-OT)/CF/R(GO-OXSWCNTs) NCs is considerably enhanced in the composite format. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) demonstrated that CF and R(GO-OXSWCNTs) were well coated by P(Py-<i>co</i>-OT). The electrical conductivity study showed that P(Py-<i>co</i>-OT) and R(GO-OXSWCNTs) might significantly improve the conductivity and the electrochemical performance of the CF. A Ga³⁺ ion selective electrochemical sensor was fabricated by coating a glassy carbon electrode (GCE) with synthesized P(Py-<i>co</i>-OT)/CF/R(GO-OXSWCNTs) NCs by using 5% Nafion binder. The slope of the calibration curve was used to calculate the sensor's analytical parameters, such as sensitivity (13.0569 μA μM^-1 cm^-2), detection limit (96.27 ± 4.81 pM), quantification limit (43.523 pM), response time, reproducibility, large linear dynamic range, and linearity. The validation of the P(Py-<i>co</i>-OT)/CF/R(GO-OXSWCNTs) NCs/GCE sensor probe was investigated by a standard addition method (recovery) in the presence of various environmental samples and satisfying results were obtained.