Study On The Band Structure Modulation And Photocatalytic Performance Of CuO Nanocluster And TiO₂ Nano-column Array Composite Structure

Titanium dioxide?TiO₂?is an effective photocatalyst that can oxidize and degrade a variety of pollutants.Due to its chemically stable,non-toxic,cheap,and commercially available,it has attracted the attention of many scientists.The bulk TiO₂ has a large bandgap and the required excitation wavelength is in the UV region.Utilization of natural solar for a photocatalytic or photoelectrochemical process can be enhanced by tuning the band gap response of titania to the visible region.The nanostructured TiO₂ has more active sites,and thus can adsorb more organic contaminants,exhibiting higher photocatalytic activity.Typical periodic one-dimensional nanostructures,such as nanowires,nanorods,and nanocolumns,can be enhanced.Charge collection,with a few grainy boundaries,increases its specific surface area and large pore volume.The cyclical one-dimensional nanostructures also have adjustable energy-saving band widths and increased electron transmission efficiency.Doping other types of semiconductors to form a heterojunction can further adjust the band gap of TiO₂,reduce the recombination rate of electron-hole pairs and increase the electron transmission efficiency.Moreover,the doped nanocluster has many excellent properties that many conventional materials do not have,and can also increase the specific surface area of one-dimensional nanostructures,thereby further enhancing the photocatalytic performance of the TiO₂material.Firstly,the Cu nanoclusters were prepared by magnetron sputtering.The effects of magnetron sputtering current,argon flow rate,and condensation zone length on the average particle size of Cu nanoclusters were investigated.The results show that with the increase of magnetron sputtering current,the average particle size of Cu clusters first increases and then decreases;with the increase of argon flow rate,the average particle size of Cu clusters also first increases and then decreases;but with the increase in the length of the condensation zone,the average particle size of Cu nanoclusters showed a gradual increase.Secondly,magnetron sputtering Oblique angle deposition?OAD?method was used and annealing treatment was combined to prepare an ordered porous TiO₂nano-column array structure.We compared optical Properties of the TiO₂ thin film,TiO₂ nanocolumn arrays on flat-base substrates and SiO₂ modified substrates,and photocatalytic activity for the degradation of methyl orange?MO?solutions were compared.The results show that,compared with the dense TiO₂ films and poorly separated arrays on a planar substrate,the ordered porous TiO₂ one-dimensional nanocolumn arrays on the SiO₂-modified substrates exhibit a wider visible light response area,and a narrow band gap,and show a good rate of photocatalytic degradation of MO.Finally,a TiO₂ thin film with a highly porous,tilted one-dimensional nanocolumn structure doped with CuO nanoclusters by magnetron sputtering OAD technology was successfully prepared.TiO₂ nanocolumn array structure and TiO₂nanocolumn array structure doped with CuO nanoclusters were prepared on the flat-base substrate and the SiO₂ modified substrate,and their optical properties and photocatalytic activity for the degradation of methyl orange?MO?solution were compared.The results indicate that the sample deposited on the SiO₂ nodified substrate?SMS?has a narrower bandgap compared to the sample deposited on the flat-base?FBS?,whether or not doped,and the photocatalytic degradation rate of the MO solution is faster;both in the FBS and the SMS Above,the samples doped with CuO nanoclusters have a narrower band gap than the undoped samples,and the photocatalytic degradation rate of the MO solution is faster.Moreover,the ordered and separated one-dimensional TiO₂ nanocolumn arrays on SiO₂ modified substrates show wide visible light response region and narrow band gap,and show the best rate of photocatalytic degradation of MO.This article is divided into six chapters.The principle and application of nanomaterials,obliquing angle deposition method and the photocatalysis principle,the advantages of photocatalysis of TiO₂ and the preparation method of its thin films are briefly introduced.The second chapter briefly introduces the method used in the experiment.In the third chapter,the preparation and particle size control of metal nanoclusters were studied.In the fourth chapter,the preparation and photocatalytic properties of TiO₂ nano-column arrays were studied.In chapter five,the preparation and photocatalytic properties of TiO₂ nanocolumn arrays doped with CuO nanoclusters were studied.The sixth chapter is summary and outlook.