Graphene Oxide‐Metal Nanoparticle Interactions and Their Application in Melamine Sensing

Melamine is an adulterant widely present in milk and milk powder industries, and has important effects on human health, therefore proposing an accurate and selective hybrid material for the detection of this molecule is of importance. In this work, the SERS effect of binding the melamine molecule to a nano‐structured hybrid rGO‐Ag 3 system has been studied by density functional theory (DFT) and its time‐dependant variant (TD‐DFT) calculations by adopting a range‐separated ω B97X‐D functional. Theoretical analysis based on the UV–vis spectra and the natural transition orbitals (NTO) of the melamine‐adsorbed hybrid rGO‐Ag 3 nanostructure system gives insights into effective enhancement factors, including static chemical enhancements and charge‐transfer (CT) enhancements. Moreover, the calculations allow proposing an explanation for the SERS spectra of melamine absorbed on silver nanoparticle in the presence and in the absence of rGO. This suggests that, theoretical methods, in particular DFT and TD‐DFT, can be used to gain microscopic insights into the functionalized graphene‐assisted SERS mechanism in nano‐structured hybrid materials for practical applications.