Microwave-rapid Synthesis Of Graphene/Silver Nanoparticles For Electrochemical Sensing

The frequently-occuring food safety issues have been a concern for years. To ensure thefood quality, new efficient high-tech detection technology is significant. Silvernanoparticles/graphene composites are of promising applications in food and bio-medicinesdetection due to its distinct optical, electrical and chemical properties, so the synthesismethods are of vital importance. However, the traditional synthesis methods of silvernanoparticles/graphene composites are time consuming with complicated operations and theresultants are less uniform in properties, therefore, great efforts have been made by scientistsfrom all over the world to develop an environmentally friendly, convenient, efficient andenergy-saving synthesis method for industrialized productions and wide applications.Thepurpose of this paper is to study a rapid, convenient and green method of synthesis of silvernanoparticles/graphene composites, and to explore its related applications in the detectionfield. The details are as follows:(1) Silver nanoparticles/graphene composites (silver nanoparticles/grapheneoxide(AgNPs-GO) and silver nanoparticles/reduced graphene oxide (AgNPs-rGO)) werefabricated by a rapid one-step microwave-assisted route.(2) We optimized the preparation conditions of AgNPs-GO, and characterized thecomposites. AgNPs-GO can be controlled by varying the molar ratio of graphene oxide (GO)and Ag(NH3)2OH, and microwave irradiation time. Otherwise, the properties of AgNPs-GOwere characterizated by ultraviolet–visible spectroscopy (Uv-vis), Fourier transform infraredspectroscopy (FTIR), Transmission electron microscopy (TEM), X-ray differaction (XRD),X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Cyclic voltammetry (CV).The results revealed that silver nanoparticles (around8nm) were uniformly dispersed andconfined by the graphene oxide. It reserved most functional groups which provided favorableconditions for loading antibody and the drug and it had surface enhanced raman spectroscopysignal which provided basis for its application in biomedicine detection.(3) We optimized the preparation conditions of AgNPs–rGO, and characterized thecomposites.The preparation of AgNPs–rGO was controlled by varying and the molar ratio ofGO,Ag(NH3)2OH, and NaOH,and microwave irradiation time.The properties of AgNPs–rGOwere characterizated by Uv-vis, FTIR, TEM, XRD, XPS and CV. Results revealed that silvernanoparticles (around19nm) were uniformly dispersed and confined by the reduced grapheneoxide sheet. Most functional groups of graphene oxide had not reserved,meanwhile theAgNPs–rGO had good electrical properties and was suitable for electrical test. Wedemonstrated a new method for highly selective Pb2+recognition using the AgNPs–rGO toconstruct Nafion/AgNPs-rGO/GCE electrode which was applied to determine trace Pb2+bydifferential pulse anodic stripping voltammetry (DPASV).The effects on experimental resultsof supporting electrolyte, pH, the preconcentration potential, the preconcentration time, theconcentration of AgNPs–rGO solution and the concentration of ethanol solution of Nafionwere examized in detail. The results showed that Nafion/AgNPs-rGO/GCE had excellentelectrochemical performance for the determination of Pb2+.The linear range is2.5~382.2 μg/L and the detection limit is0.9μg/L.The Nafion/AgNPs-rGO/GCE was successfullyapplied to determine trace Pb2+in tea samples and the results were in agreement with those ofgraphite furnace atomic absorption spectrometry with the actual application value.