Rapid and highly selective electrochemical sensor based on ZnS/Au-decorated f-multi-walled carbon nanotube nanocomposites produced via pulsed laser technique for detection of toxic nitro compounds.

Novel ZnS/Au/f-multi-walled carbon nanotube (MWCNT) nanostructures were produced via a pulsed laser-assisted technique followed by a wet chemical process. ZnS nanospheres were synthesized via pulsed laser ablation of a Zn target in DMSO, which was used as a solvent and sulfur source. Notably, no additional sulfur sources, surfactants, or reducing agents were used during the synthesis. The structure and morphology of the prepared materials were characterized by X-ray diffraction, micro-Raman spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The fabricated electrochemical sensor based on ZnS/Au/f-MWCNT nanocomposites exhibited rapid and highly selective detection of a toxic pollutant, namely 4-nitrophenol (4-NP). Linear sweep voltammetry analysis revealed that the optimized ZnS/Au10/f-MWCNT3 nanocomposite displayed a wide linear dynamic response (10-150 μM) with high sensitivity (0.8084μAμM-1cm-2) and low limit of detection (30 nM). The excellent 4-NP sensing performance of the modified electrode was attributed to the availability of numerous active sites (electrochemical surface area=0.00369μFcm-2) and an enhanced electron transfer rate. Interference and stability studies were also conducted. A 100-fold excess of competing ions (Na+, K+, Mg2+, Cl-, NO3-, 4-AP, AA, and 2-NP) did not interfere with the selective detection of 4-NP. The newly fabricated ZnS/Au10/f-MWCNT3 nanocomposite could be an effective sensor for the selective and sensitive detection of toxic organic nitro compounds.