Preparation And Photoelectrochemical Properties Of One-dimensional TiO₂ Nanoarray Heterojunction

Titanium dioxide?TiO₂?nanomaterials are widely used in thin film solar cells,solar water decomposition systems,gas sensors and biomaterials due to their stable chemical properties,low cost,easy preparation,non-toxicity,and appropriate energy level structure.Among different titanium dioxide nanomaterial structures,one-dimensional titanium dioxide nanorod arrays have unique optical and electrical properties,high orderliness,large specific surface area,and good electron transmission channels,which have attracted more and more attention.Titanium dioxide nanowires?TNW?and titanium dioxide nanorods?TNR?provide direct channels for electron transport in semiconductors due to their unique one-dimensional structures,effectively reducing the electron-hole recombination rate.Secondly,due to the large specific surface area of the one-dimensional structure,the sample is in sufficient contact with the electrolyte or methyl orange solution,which effectively promotes the transport and transfer of electrons,and has more prominent photoelectrochemical properties and pollutant degradation capabilities.In this paper,one-dimensional TNR and TNW are selected as research substrates,and metal,non-metal and semiconductor modified composite arrays are constructed by chemical-physical methods.The samples are characterized and tested,and their photoelectrochemical properties are discussed.The main research contents are as follows:A highly ordered TiO₂ nanorod array was grown on a conductive glass FTO by a simple hydrothermal method,and then annealed in the air environment.Subsequently,BiOI nano flower pieces were grown on the surface of TiO₂ nanorods by the secondary hydrothermal method to prepare BiOI/TiO₂ samples with different concentration gradients.And by using the redox reaction method,the BiOI/TiO₂ sample was immersed in an AgNO₃ solution,and placed under an ultraviolet lamp for a period of time to successfully prepare an Ag/BiOI/TiO₂ sample.The composition,morphology and photoelectrochemical properties of the samples were studied.The results show that the addition of Ag and BiOI successfully constructed a Z-type heterojunction structure,thereby significantly improving the photoelectrochemical performance of the composite array.The surface plasmon resonance?LSPR?effect of silver quantum dots?Ag QDs?further increased.The ability of the sample to absorb light.Ti³⁺ions were introduced by annealing a TNW array in a hydrogen atmosphere high temperature tube furnace.TNW is prepared by adding an appropriate amount of glacial acetic acid and adjusting the appropriate temperature to the basic solution prepared by the original TNR,and finally an island-shaped TNW array is obtained.The effect of different annealing temperatures on the amount of Ti³⁺ions was studied.On the basis of ensuring the conductivity of FTO,the temperature range was set at 150-450?.The experimental results show that Ti³⁺ion doping greatly improves the performance of the original TNW array.Through further investigation,it was found that the optimal amount of Ti³⁺ions was introduced during annealing at 350?.The crystal phase,structure and morphology of the sample were analyzed in detail,and the photoelectrochemical performance of the sample was determined by an electrochemical workstation.The photocatalytic performance of the sample was determined by degrading methyl orange.The preparation of novel island-like nanowires and self-doping of Ti³⁺ions are expected to become potential materials for the synthesis of other new photocatalysis.For the first time,the construction of a TiO₂/BTO/MoS₂ coaxial core-shell P-N heterojunction structure was proposed,and the optimal MoS₂ coverage concentration was explored.The polarization electric field induced by the polarization charge effectively promotes and inhibits the recombination of photogenerated electrons and holes generated by TiO₂ and MoS₂.The two-dimensional MoS₂ flower sheet structure greatly improves the specific surface area of the heterostructure,and the P-type MoS₂ with a narrow band gap?1.8eV?broadens the spectrum utilization,and needs to provide more activity in the reaction solvent as a photocatalyst.At the site,MoS₂ just meets the condition due to its flower structure.TiO₂/BTO/MoS₂ ternary heterostructure nanorod arrays can effectively improve the photocatalytic activity and stability of photocatalysts.This study opens up a new way for the improvement of P-N heterojunction performance and piezoelectric effect.