Synergistic activation of lamellar bismuth selenide anchored functionalized carbon nanofiber for detecting hazardous carbendazim in environmental water samples.

Pesticides pollute natural water reservoirs through persistent accumulation. Therefore, their toxicity and degradability are serious issues. Carbendazim (CBZ) is a pesticide used against fungal infections in agricultural crops, and its overexploitation detrimentally affects aquatic ecosystems and organisms. It is necessary to design a logical, efficient, and field-deployable method for monitoring the amount of CBZ in environmental samples. Herein, a nano-engineered bismuth selenide (Bi2 Se3 )/functionalized carbon nanofiber (f-CNF) nanocomposite was utilized as an electrocatalyst to fabricate an electrochemical sensing platform for CBZ. Bi2 Se3 /f-CNF exhibited a substantial electroactive surface area, high electrocatalytic activity, and high conductivity owing to the synergistic interaction of Bi2 Se3 with f-CNF. The structural chemical compositions and morphology of the Bi2 Se3 /f-CNF nanocomposite were confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FESEM). Electrochemical analysis was carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The voltammetry and impedance experiments exposed that the Bi2 Se3 /f-CNF-modified GCE has attained adequate electrocatalytic function with amended features of electron transportation (Rct  = 35.93 Ω) and improved reaction sites (0.082 cm2 ) accessible by CBZ moiety along with exemplary electrochemical stability (98.92%). The Bi2 Se3 /f-CNF nanocomposite exhibited higher sensitivity of 0.2974 μA μM-1 cm-2 and a remarkably low limit of detection (LOD) of 1.04 nM at a broad linera range 0.001-100 μM. The practicability of the nanocomposite was tested in environmental (tap and pond water) samples, which supports excellent signal amplification with satisfactory recoveries. Hence, the Bi2 Se3 /f-CNF nanocomposite is a promising electrode modifier for detecting CBZ.