This study presents the synthesis of CO3O4–ZrO2 (CZ) doped Graphene nanoplatelets (GNPs) composite (GNPs-CZ) via simple co-precipitation route and was drop casted on carbon fiber paper (CFP) to fabricate the modified electrochemical sensor (GNPs-CZ/CFP) electrode for sensitive determination of phenol (Ph) in 0.1 M phosphate buffer solution (PBS). The physico-chemical characterization was done by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). GNPs-CZ composite exhibits enhanced electrochemical behavior towards Ph as shown by voltammetric techniques. The enhanced electro-oxidation of Ph was attributed to the joint efficiency of GNPs and CZ. Co3O4 being very surface sensitive to carbonate species; the introduction of ZrO2 to it stabilizes its active sites and enhances the decomposition of carbonate. Electrode fouling is the prime hurdle in electrochemical detection of Ph as the bare electrode gets poisoned due to dimerization of phenol and the oxidation current decreases. This challenge was removed by coating the bare electrode with GNPs-CZ composite. The addition of GNPs effectively improves the surface area, and enhances the electrons transfer rate showing better electrocatalytic response. A higher sensitivity (748 μA mM˗1), appreciable detection limit (74 μM), and wide linear range (20˗400 μM) with good stability are achieved. Thus, the GNPs-CZ/CFP electrode has the potential to be used as Ph electrochemical sensor for pollution control scenario.
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