Preparation Of Titanium Dioxide Nanomaterials And Their Degradation Performance

TiO₂,one of the most commonly used semiconductor photocatalysts,has the features of non-toxic,stable photocatalytic properties,low cost and so on.However,the largescale practical application of Ti O2 has been hampered by the disadvantages of high recombination of photogenerated carriers,low light-absorbed ability and large band gap.Therefore,improving the separation of photogenerated carrier pairs and extending the light-absorbed spectra of Ti O2 photocatalysts for effectively photodegrading pollutants under solar light are very significant for ecology protection.To overcome the shortcomings of Ti O2 photocatalysts,this paper aims to design surface hierarchical nanostructures and introduce narrow-band-gap guest phase（C3N4）on the electrospinning-derived Ti O2 fibers.The main researching contents and results are as follows:（1）Electrospinning method combined with room-temperature hydrothermal approach were developed to construct a series of Ti O2-based fibers with various surface hierarchical morphologies by simply adjusting the reaction conditions or selecting different precursor templates.As-prepared Ti O2 photocatalyst has large specific surface area（140 190 m2 g-1）and abundant pore structure.This is beneficial to enhance the scattering and utilization of light and shorten the optical carrier transport path.Under UV light for 30 minutes,Ti O2 fibers with cage-like surface morphology show the optimized photocatalytic degradation efficiency for Rhodamine-B（94.3%）and 2,4-dichlorophenol（92%）,delivering an excellent UV-induced photocatalytic performance.（2）Ti O₂/C₃N₄ visible-light photocatalysts with heterojunction composite structure were prepared by calcination of polymer/thiourea/tetrabutyl titanate nanofibers in air atmosphere.The introduction of ultrafine C3N4 results in the formation of heterojunction,and thus improved visible-light absorbed capability.Moreover,in-situ formation of C3N4 in the Ti O2-based composite fibers can induces the exposure and growth of anatase Ti O2 and the ability of catalyst to generate ·OH radical from water cracking can be increased.The result showed that Ti O2/C3N4 composite catalyst showed good visible light catalytic activity,with a removal rate of 94.6% and a degradation rate of 0.015 min-1 for 2,4-DCP under 180 min of visible light.The composite catalyst still has good photocatalytic activity and recycle ability under low temperature and acidic environment.