Graphene nanosheets-supported Ag nanoparticles for ultrasensitive detection of TNT by surface-enhanced Raman spectroscopy

Sensitive and selective detection of 2,4,6-trinitrotoluene (TNT) has attracted considerable attention due to the wide applications of TNT as explosive material . Many efforts have been made to develop various sensors for detecting TNT in recent years. We herein report a novel sensor based on p-aminothiophenol (PATP) functionalized silver nanoparticles supported on graphene nanosheets (Ag/GNs), which was found to be a kind of effective chemosensor for the ultratrace detection of TNT by using surface enhanced Raman scattering (SERS). In the present hybrid material, PATP is paired together to form a corresponding azo compound p, p′-dimercaptoazobenzene (DMAB) and thus can be used as a model Raman probe. The π-donor–acceptor interaction between π-acceptor TNT and π-donor DMAB-Ag/GNs complex can effectively induce the “hot spots” for SERS. The intense spectral resonance from the DMAB–TNT–DMAB bridges formed between the Ag/GNs nanosheets could result in enhanced Raman signals of DMAB molecules with the presence of ultratrace TNT. SERS measurements demonstrated that TNT with concentration as low as 10 −11   M can be detected by using the present SERS platform. The present study not only provides a facile method for ultrasensitive and selective detection of TNT but also could develop a graphene-based SERS platform.