Prpartion Of Multiaxial Nanofibers By Electrospinning And Its Photoeletrocatalytic Properties

In recent decades,with the rapid development of society and economy,serious environmental pollution has inevitably been caused.Semiconductor photoelectrocatalytic technology is a feasible method for environmentally friendly and effective degradation of organic pollutants.Preparation of novel,unique and multifunctional photocatalysts is considered to be the key to the practical application of photoelectrocatalytic technology.Among many photocatalytic materials,fiber electrodes can not only be recycled,but also improve the catalytic efficiency through the synergistic effect of external voltage and photocatalysis.Electrospinning is an electrostatic spinning method that uses high-voltage static electricity as the driving force to prepare organic polymer nanofibers through a nozzle.A precursor solution was prepared by a sol-gel process from polyvinylpyrrolidone?PVP?,the metal semiconductor source was zinc acetate and silver acetylacetonate.Coaxial electrospinning technology and heat treatment were used to prepare ZnO/Ag₂O/FTO coaxial nanofibers?FTO:conductive glass?.Taking the Xenon lamp as the visible light source for simulation and methylene blue as the target degradation product,the photoelectrocatalytic activity of the prepared nanofibers was investigated.The results show that the coaxial ZnO/Ag₂O nanofibers have a shell-like similar structure?outer ZnO;inner Ag₂O?.The heterojunction is formed by Ag₂O and ZnO,which reduces the band gap energy of ZnO and improves the utilization of visible light.In visible light,compared with pure ZnO,ZnO/Ag₂O has a strong photoelectrocatalytic capacity,and the amount of Ag₂O has a great impact on the photoelectrocatalytic activity of coaxial fiber.Under the same photoelectrocatalytic conditions,the ZnO/Ag₂O-7 coaxial nanofiber has the best photocatalytic efficiency,with a degradation rate of 93.36%,and its maximum kinetic constant is 1.13×10^-2 min^-1.BiVO₄/CoO/FTO coaxial nanofibers were prepared by using the same material preparation process,and using the same fiber template and preparation of precursor solution method,and FTO as the carrier.The outer layer solution was prepared with bismuth triflate and vanadium acetylacetonate as the source of BiVO₄,and a inner layer solution was prepared with cobalt acetylacetonate.After research,it was found that BiVO₄?outer?/CoO?inner?coaxial nanofibers have high crystallinity monoclinic scheelite after 500°C heat treatment,and the fiber structure is continuous and porous.The fiber not only retains BiVO₄ characteristics,but also combines with hexagonal CoO to build a heterojunction to red-shift the light absorption region,reduce the band gap value,and expand the visible light response range.The fluorescence spectrum analysis combined with the photocurrent test found that BVC-0.6 coaxial nanofibers have the best separation of photogenerated electron and hole pairs.It was also found that the catalytic performance of BiVO₄/CoO was gradually improved by the same performance test method as the content of CoO increased.The photoelectrocatalytic effect of BVC-0.6 reached a maximum of 92.62%,which was an increase of 22.66%compared to BV.With glacial acetic acid,DMF and ethanol as solvents,the outer layer solution uses bismuth triflate as the bismuth source,the middle layer solution uses palladium acetate as the palladium source,and the inner layer solution uses silver acetylacetonate as the silver source.Bi₂O₃?outer?/PdO?middle?/Ag₂O?inner?/FTO photoelectrode was prepared by triaxial Electrospinning Technology.Characterization analysis of the triaxial structure of the BPA materials tetragonal PdO,hexagonal Ag₂O and hexagonal Bi₂O₃did not affect the crystal growth between each other.The BPA material has good absorption in the visible light region,and the BPA charge is effectively separated by combining work function and fluorescence spectrum analysis,which makes the BPA catalytic ability stronger than the coaxial Bi₂O₃?outer?/PdO?inner?material.Among them,BPA-2 has the best photocatalytic effect,which is superior to photocatalysis and electrocatalysis,with a degradation rate of 95.58%.It is possible that the interfaces between Bi₂O₃,PdO,and Ag₂O on Bi₂O₃/PdO/Ag₂O coaxial fibers have different degrees of heterojunctions.The photogenerated electron-hole pair is effectively separated due to the synergistic effect of heterojunction and photoelectricity,thereby improving the photoelectrocatalytic performance of the material.In addition,possible optoelectronic mechanisms are proposed.