Synthesis and Characterization of Samarium-Substituted Molybdenum Diselenide and Its Graphene Oxide Nanohybrid for Enhancing the Selective Sensing of Chloramphenicol in a Milk Sample

The electronic conductivity and electrocatalytic activity of metal chalcogenides are normally enhanced by following the ideal strategies such as substitution/doping of heterogeneous atoms and hybridization of highly conductive carbon supportive materials. Here, a rare earth element (samarium) was substituted with MoSe₂ using the simple hydrothermal method. The lattice distortion due to the substitution of Sm³⁺ with MoSe₂ was clearly observed by using high-resolution transmission electron microscopy analysis. As a consequence, the prepared SmMoSe₂ nanorod was encapsulated with graphene oxide (GO) sheets by using ultrasonication process. Furthermore, the GO-encapsulated SmMoSe₂ nanocomposite modified glassy carbon electrode (GO@SmMoSe₂/GCE) was used for the sensing of chloramphenicol. The results showed that the GO@SmMoSe₂/GCE revealed the superior electrocatalytic activity with low detection (5 nM) and sensitivity (20.6 μA μM^-1 cm^-2) to electrochemical detection of proposed analyte. It indicates that the substitution of Sm³⁺ and encapsulation of GO significantly increased both the electrical conductivity and electrocatalytic activity of MoSe₂.