Study On Fabrication And Electrochemical Applications Of Electrospun Nanofibers

Electrospinning is a relatively simple and versatile method to produce polymerfibers with diameters ranging from several nanometers to micrometers. Here,one-dimensional metal oxides nanomaterials fabricated by electrospinning methodand followed calcination were used for electrochemical applications.Firstly, a glucose sensor was based on NiO nanofibers and graphene oxide. TheNiO nanofibers were fabricated by electrospinning and followed calcination andgraphene oxide was reduced by environmentally electrochemical method. The sensorwas characterized by scanning electron microscopy （SEM）, energy dispersive X-rayspectroscopy （EDX）, X-ray photoelectron spectroscopy （XPS） and electrochemicalimpedance spectroscopy （EIS）. The sensor exhibited high sensitivity (1100μAmM^-1cm^-2) from0.002to0.60mM, low detection limit of0.77μM （S/N=3）, longterm stability and excellent anti-jamming ability in glucose determination. The sensorwas further applied to detection of glucose in human blood serum sample, and theresults accorded with those of commercial test.Secondly, a hydrogen peroxide sensor was based on PdO-NiO compositenanofibers which were synthesized by the combination of electrospinning andfollowed thermal treatment processes. Scanning electron microscopy （SEM）, energydispersive X-ray spectroscopy （EDX）, X-ray diffraction （XRD）, and X-rayphotoelectron spectroscopy （XPS） were adopted to characterize the structure andcomposition of the composite. The influential factors such as the composition,amounts of nanofibers, and applied potential were also studied. The sensor exhibitedhigh sensitivity (583μA mM^-1cm^-2), a wide linear range from0.005to19mM andlow detection limit of2.94μM （S/N=3） for H₂O₂determination. Adding properproportion NiO seemed to be a simple and effective way to improve the activity ofPdO catalysis. Lastly, PdO-Co₃O₄composite nanofibers were fabricated by electrospinning andfollowed calcination. The electrochemical pretreatment of nanofiber modifiedelectrode in sulfuric acid to dissolve Co₃O₄on the surface could significantly increasethe active area. Scanning electron microscopy （SEM）, energy dispersive X-rayspectroscopy （EDX）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy（XPS） were adopted to characterize the materials. The electrode showed goodmethanol electrooxidation activity and stability, suggesting that PdO-Co₃O₄nanofibers were promising for applications in alkaline direct methanol fuel cells（DMFCs）.