| Transition metal nanomaterials,(e.g.,TiC,NiCo2O4 and NiCo2S4)have been attracted increasing interest due to their merits of simple preparation,low cost,low toxicity,controllable morphology and high electrochemical activity.However,the pure transition metal nanostructures are tend to agglomerate,resulting in the decrease of effective area and properties.Electrospun(graphitized)carbon nanofibers(CNFs/GCN)can not only improve the nanomaterials loading,reduce agglomeration and increase the surface area,but also effectively improve the conductivity of nanomaterials because of its large specific surface area,good conductivity,high mechanical strength and easy functionalization.In this thesis,CNFs and GCN were used as substrates to support TiC nanoparticles(TiC/CNFs),NiCo2O4 and NiCo2S4 nanoneedle(NiCo2O4/GCN,NiCo2S4/GCN).The applications of composite in the construction of glucose,ascorbic acid(AA),dopamine(DA)and uric acid(UA)biosensors and energy storage performance of supercapacitors were explored.The main works are as follows:(1)TiC/CNFs was synthesized by one-step via electrospinning and carbonization technology.It was utilized to immobilize glucose oxidase and its sensing performance was explored.Scanning electron microscope(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray electron energy spectrum(XPS)and thermo-gravimetric analysis(TGA)characterizations results showed that TiC nanoparticles(NPs)firmly embedded in the CNFs frameworks.TiC/CNFs displayed a three-dimensional(3D)porous network structure and owned good thermal stability.TiC/CNFs has excellent electrocatalytic activity for glucose oxidation.The as-proposed sensor possessed wide linear range(0.013-10.5 mM,R2=0.999),low detection limit(3.7 ?M,S/N = 3),high sensitivity and strong anti-interference ability,providing a new sensing platform for glucose detection.(2)TiC/CNFs was further used to construct AA,DA and UA sensors due to its simple preparation,high conductivity and electrocatalytic activity.The prepared sensor with wide linear range,low detection limit and good selectivity can detect AA,DA and UA selectively or simultaneously,and successfully used in actual sample analysis.When AA,DA and UA were detected simultaneously,the linear ranges were 0.025-1.25 mM,0.05-45 mM and 0.005-0.775 mM,with detection limits of 1,0.02 and 0.2 ?M,respectively.(3)NiCo2O4/GCN was fabricated by hydrothermal method using GCN as substrate,and it was applied for the construction of glucose sensor.NiCa2O4 nanoneedles growed uniformly on GCN ascribed to the introduction of GCN with 3D network structure and good conductivity,increasing the specific surface area and conductivity of the composites.The non-enzymatic glucose sensor showed fast response,wide linear range(5?M-19.175 mM,R2 = 0.998),low detection limit(1.5 ?M,S/N = 3),high sensitivity(1947.2?A mM-1 cm-2),good reproducibility and high selectivity.(4)NiCO2S4/GCN was prepared by two-step hydrothermal approach,and the effects of reaction time on its morphology and electrochemical properties were investigated.The composite with core-shell NiCo2S4 nanoneedles grow uniformly and excellent electrochemical properties was obtained by reacting at 160? for 7 h(NiCo2S4/GCN-7).The as-prepared sensor possessed excellent sensing properties with wide linear range(0.0005-3.571 mM,R2 = 0.995),low detection limit(0.167 ?M,S/N = 3),high sensitivity(7431.96?A mM-1 cm2),good selectivity,strong anti-interference ability and high reproducibility.(5)NiCo2S4/GCN was used as supercapacitor electrode material,owning to their large surface area and good conductivity.NiCo2S4/GCN displayed high specific capacity(1969.4 F g-1,0.5 A g-1),good rate performance and cycle stability.Meanwhile,the asymmetric supercapacitors assembled with NiCO2S4/GCN as positive electrode and activated carbon materials as negtive electrode also presented high specific capacity,outstanding energy density(111.2 Wh Kg-1,385.0 W Kg-1)and cycle stability,indicating that NiCo2S4/GCN has great potential application in supercapacitors. |
PDF Full Text Request