Fabrication Of Titania Based Thoroughly Mesoporous Nanofibers With Tailored Structures And Their Photocatalysistic Activities

Mesoporous nanofibers are considered as not only possess theadvantages of one-dimensional nanomaterials, but also have the uniqueproperties of mesoporous structure with high surface areas and lagre porevolume, which favor its more novel multiple functional characteristics and pushforward its practical application, such as, catalyst, energy, sense and medicaltreatment.Centering on the research and development of efficient photocatalyst,this research project aims at the the study of a general strategy to preparation ofmesoporous nanofibers, namely foaming-assisted electrospinning, and a seriesof innovative exploration has been made to achieve the tailoring synthesis ofsemiconductor thoroughly mesoporous nanofibers. TiO2materials wereexampled as the research objects and TiO2thoroughly mesoporous nanofiberswith high purity and well-controlled structure were primarily prepared byoptimizing the technology parameters of this new method. Then, in order torestrain photon-generated carrier recombination and broaden the light response range, we further study the hollow structure, doping, loaded with preciousmetals and broadband/narrow band gap composite materials, which aim to thefabrication of the TiO2based thoroughly mesoporous nanofibers withstrengthening photocatalytic performance. The main progresses of this workhave been made as bellow:(1) Polyvinylpyrrolidone (PVP), butyl titanate (TBOT) and diisopropylazodicarboxylate (DIPA) were dissolved in the mixed solvent of absolute ethylalcohol and acetic acid. The organic precursor fibers have been fabricated byelectrospinning. The obtained precursor fibers were then calcinated in air,leading to the fabrication of TiO2thoroughly mesoporous nanofibers. The resultsconfirmed that the thoroughly mesoporous nanofibers with high purity andwell-controlled structure could be preparated by the present strategy, whichintroduce the foaming technology to the traditional electrospinning process. TheBET analysis suggest the specific surface area is ca.~6times compared to theordinary solid nanofibers. The photocatalytic activities of the as-fabricated TiO2thoroughly mesoporous products exhibit improved activity and the highesthydrogen production rate is ca.~2times to that of the ordinary solid nanofibersas well as P25.(2) Introducing paraffin oil and surfactant to the soltions, TiO2hollowthoroughly mesoporous fibers were synthesized via the foaming-assistedelectrospinning method and the obtained TiO2products possess the mixed-phaseof anatase and rutile as well as P25. The results suggest that the obtained thoroughly mesoporous TiO2hollow fibers exhibited improved performance andits hydrogen production and RhB removal rate is ca.~2.5times compared to thatof P25.(3) Introducing AgNO3as Ag source, Ag@TiO2thoroughlymesoporous nanofibers were fabricated via the foaming-assisted electrospinningmethod or photodeposition. The results suggest the Ag@TiO2thoroughlymesoporous nanofibers exhabit the enhanced photocatalytic activity and thierhydrogen production rate is more than~4times and~2times compared to thatof pure TiO2ones, respectively.(4) Introducing Cu(Ac)2as Cu source, TiO2-CuO-Cu thoroughlymesoporous nanofibers were fabricated via the foaming-assisted electrospinningmethod. By varying the Cu(Ac)2content in the initial solutions, the phasecomposition of the mesoporous nanofibers could be tailored as TiO2/CuO,TiO2/Cu andTiO2/CuO/Cu. The results suggest the ternary TiO2/CuO/Cuthoroughly mesoporous system exhibited prominent photocatalytic ability andits hydrogen production rate is more than~4times to that of the pure TiO2ones.(5) Introducing urea as nitrogen source, N-doped TiO2thoroughlymesoporous nanofibers were prepared by the foaming-assisted electrospinningmethod. The results indicate that the N doped products possess the red shift ofits absorption threshold and obviously improved visible light response. Thevisble light photocatalytic results disclose that the N doped thoroughlymesoporous products exhibit an enhanced photocatalytic activity and its RhB removal rate is more than3.5times compared to that of pure TiO2ones.(6) Introducing WCl6as W source, TiO2/WO3thoroughly mesoporousnanofibers were prepared by the foaming-assisted electrospinning method. Then,the result TiO2/WO3/g-C3N4ternary thoroughly mesoporous nanofibers wereobtained by loaded the foliated graphite C3N4.The results suggest theTiO2/WO3/g-C3N4ternary thoroughly mesoporous nanofibers exhibit anenhanced photocatalytic activity under visible light irradiation and its hydrogenproduction rate is more than~65times to that of the the pure TiO2ones.