Preparation And Properties Of Heterostructures Electrospun Polyimide Hybrid Nanofibers

In recent years,electrospinning has been established as an efficient technique for producing nanofibers with controllable diameter,large specific surface area,and high porosity.Electrospun nanofibers can be used as substrates for the design and construction of novel hybrid nanofibers with heterostructures that have drawn considerable attention as they can provide ideal performance.Owing to the well-designed structure and the synergistic effects among individual components,hybrid nanofibers have been applied for the generation of nanosized multifunctional devices,which are crucial in energy storage systems,biotechnology,and so on,as electrode materials used in supercapacitors and lithium-ion batteries,field-effect transistors and gas sensors,as well as portable electronics and electric vehicles.In this work,we promote a simple and efficient approach providing high-quality vertical TiO2 nanorod arrays on the surface of PI nanofibers to generate PI-TiO2,which can be used as substrate to load silver(Ag)nanoparticles,to grow ZIF-8nanoparticles and g-C3N4 nanosheets,respectively.Finally,the hybrid nanofibers with a well-designed structure are obtained.Therefore,our as-prepared hybrid nanofibers can be utilised for the efficient degradation of organic dyes,which has important applications in water purification.In this work,the polyamic acid(PAA)precursor solution was synthesized by low-temperature polycondensation method.PI nanofibers formed from the PAA with imidization at 300 ? for 2 h.Then,with the combination of hydrothermal method and UV irradiation,we generated PI-TiO2 and PI-TiO2@Ag,respectively.PI-TiO2@Ag hybrid nanofibers exhibited a more remarkable degradation activity.Under UV irradiation for 120 min,the degradation rate of Rh B for PI-TiO2@Ag samples was about 97%,demonstrating that silver nanoparticles can improve the photocatalytic efficiency of PI-TiO2.In this work,using in-situ growth to prepare ZIF-8 nanoparticles onto PI-TiO2 to obtain PI-TiO2@ZIF-8 hybrid nanofibers,which was similar to sea buckthorn.After UV irradiation for 90 minutes,photocatalytic degradation of Rh B for PI and PI-TiO2 belonged to first-order kinetics,PI-TiO2@ZIF-8 belonged to quasi-first-order kinetics.The degradation rate of Rh B for PI-TiO2@ZIF-8 was about 98%,this excellent photocatalyticperformance was mainly attributed to the heterostructure and synergistic effect established between TiO2 nanorods and ZIF-8 nanoparticles.A simple and efficient method was proposed for PI-TiO2@g-C3N4 hybrid nanofiers by using high temperature pyrolysis of melamine to prepare g-C3N4 nanosheets onto PI-TiO2.After visible light for 120 minutes,photocatalytic degradation of Rh B for PI-TiO2 and PI-TiO2@g-C3N4 belonged quasi-first-order kinetics.The degradation rate of Rh B for PI-TiO2@g-C3N4 was about 93%,the excellent photocatalytic performance of PI-TiO2@g-C3N4 was mainly owning to the heterojunction and synergistic effect established between TiO2 nanorods and g-C3N4.