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

Abstract

In this study, we report a novel ternary conductive hybrid material with high stability, conductivity, and excellent electrochemical Ga³⁺ sensing ability. Ternary poly(pyrrole-co-o-toluidine)/CoFe₂O₄/reduced graphene oxide–oxidized single-wall carbon nanotube nanocomposites in the form of P(Py-co-OT)/CF/R(GO–OXSWCNTs) NCs have been synthesized through an in situ chemical polymerization method via 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 via co-reduction of graphene oxide along with oxidized SWCNTs flowed by coating CF and R(GO–OXSWCNTs) with a poly(pyrrole-co-o-toluidine) matrix P(Py-co-OT) copolymer. The results of X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR) and Raman indicated that the P(Py-co-OT)/CF/R(GO–OXSWCNTs) NCs were effectively synthesized with strong interactions among the constituents. The thermal stability of P(Py-co-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-co-OT). The electrical conductivity study showed that P(Py-co-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-co-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-co-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.