Electrospinning Preparation And Photocatalytic Performance Of Nanofibers Loaded With ZnO

ZnO is an excellent photocatalytic material with high photosensitivity,non-toxicity and wide band gap.It has a good application in the degradation of pollutants in water.However,there are many problems in the application of ZnO powder,such as agglomeration and recycling.How to achieve the dispersion,fixation and recycling of ZnO powder to meet the requirements of practical application is still a challenge.In recent years,one-dimensional carbon nanofibers?CNF?have attracted more and more attention because of their small size.CNF can achieve uniform immobilization of catalysts,improve the agglomeration of catalysts,transfer photogenerated electrons and inhibit the recombination of electron-hole pairs,which are conducive to the improvement of photocatalytic performance.Therefore,in order to prepare composite nanofibers with excellent photocatalytic performance in this paper,we use nanofibers as carriers,nano-zinc oxide as the target photocatalyst,the following research works have been carried out:?1?Porous nanofibers containing ZnO were prepared by electrospinning and annealing using polyacrylonitrile?PAN?and zinc chloride?ZnCl₂?.The microstructure of samples showed that there are many porous structures on the surface of the fibers,and the number of pores is related to the amount of ZnCl₂.Component analysis results show that porous nanofibers are composed of amorphous carbon and ZnO.The photocatalytic properties were investigated by using simulated sunlight and methylene blue?MB?.The results showed that the porous nanofibers with 5 wt%ZnCl₂ in the precursor have the best photocatalytic performance.The existence of porous structures are beneficial to the photocatalytic activity.?2?Hollow nanofibers were prepared by electrospinning and annealing using PAN and PMMA.N-ZnO were loaded on the surface of hollow nanofibers and porous nanofibers by hydrothermal method.The results showed that with more PMMA the hollow structure became more complete.The loaded ZnO particles were evenly dispersed on the surface of nanofibers.The photocatalytic properties results showed that the photocatalytic degradation rate of MB by porous nanofibers loaded with ZnO particles reached more than 60%in 150minutes,the porous nanofibers with 5 wt%ZnCl₂ in the precursor reached 91%.The degradation rate are over 70%in 150 minutes after loading ZnO particles on the surface of hollow nanofibers,the degradation rate of hollow nanofibers with PAN:PMMA=1:2 in the precursor reached 99%.Hollow nanofibers exhibited better photocatalytic performance than porous fibers,which was due to the larger specific surface area and the adsorption capacity increased.?3?Using hollow nanofibers as carriers,hollow nanofibers composites loaded with hexagonal-ZnO were prepared by hydrothermal method.The results showed that the hexagonal-ZnO uniformly loaded on the surface of hollow nanofibers.The photocatalytic properties tests showed that the photocatalytic properties of hollow nanofibers composites were improved with the size of hollow structure,all of the samples reached more than 70%in 150 minutes,the degradation rate by PAN:PMMA=1:2 in the precursor reached 99%within 100 minutes.The photocatalytic activity of porous nanofibers loaded with ZnO particles is superior because there are more active site;the photocatalytic activity of hollow nanofibers loaded with ZnO particles is superior to the porous nanofibers loaded with ZnO particles because the hollow nanofibers have larger specific surface area,which can further increase the adsorption performance;the photocatalytic performance of hollow nanofibers loaded with hexagonal-ZnO is better than the hollow nanofibers loaded with ZnO particles because the former have more active sites and the structure of hexagonal-ZnO can also increase the adsorption performance.