Identifying Superior Binding Sites for Lead Detection on Solvothermally Engineered Fluorescent Active Heteroatom‐Doped Carbon Nanofibers

Aiming to decipher the role of optimum binding site for detection of lead ions, fluorescent active heteroatom‐doped carbon nanofibers‐based materials (O‐CNF, N‐CNF, sulfur‐containing material (S‐CNF), and NS‐CNF) are fabricated solvothermally. The S‐CNF exhibits highest detection efficiency for fluorescent sensing of lead ions as compared to other materials. The S‐CNF detects lead ions with 5.99 μM detection limit in a concentration range of 0–40 μM. FESEM and HRTEM analysis of S‐CNF reveals the hybrid morphology, where spherical units formed from elemental sulfur are aggregated on the surface of carbon nanofibers. X‐ray diffraction pattern reveals amorphous nature of the material, and incorporation of sulfur atom is confirmed through X‐ray photoelectron spectroscopy. Various functional groups such as >CO, ROR, COOH, SO, SS, CSC, and CS are found to be present in S‐CNF. The binding sites for the lead ions are confirmed by adsorbing the metal ions on S‐CNF surface that are clearly seen on FESEM–EDS analysis. The final proof for the involvement of SO and other sulfur‐bearing functional groups (SS, CSC, and CS) is performed by Fourier‐transform infrared spectroscopy. The investigation clarifies role of various oxygen‐, nitrogen‐, and sulfur‐containing functional groups for the efficient removal of toxic lead metal in contaminated water samples.