Magnetic MoS₂ on multiwalled carbon nanotubes for sulfide sensing

A novel hybrid metallic cobalt insided in multiwalled carbon nanotubles/molybdenum disulfide (Co@CNT/MoS₂) modified glass carbon electrode (GCE) was fabricated with a adhesive of Nafion suspension and used as chemical sensors for sulfide detection. Single-layered MoS₂ was coated on CNTs through magnetic traction force between paramagnetic monolayer MoS₂ and Co particles in CNTs. Co particles faciliated the collection of paramagnetic monolayer MoS₂ exfoliated from bulk MoS₂ in solution. Amperometric analysis, cycle voltammetry, cathodic stripping analysis and linear sweep voltammetry results showed the Co@CNT/MoS₂ modified GCE exhibited excellent electrochemical activity to sulfide in buffer solutions, but amperometric analysis was found to be more sensitive than the other methods. The amperometric response result indicated the Co@CNT/MoS₂-modified GCE electrode was an excellent electrochemical sensor for detecting S^2- with a detection limit of 7.6 nM and sensitivity of 0.23 mA/μM. The proposed electrode was used for the determination of sulfide levels in hydrogen sulfide-pretreated fruits, and the method was also verified with recovery studies.