Synthesis And Research Of Low Dimensional TiO₂ Visible Light Photocatalysts

As an important part of nanomaterials,TiO₂ shows huge volume effect,surface effect,color effect and wonderful optical properties.And it was used widely in more and more fields as a new material,especially in photocatalysis,for its optical, electrical and magnetic characterization.Since 1972,Fujishima et al.found the photo-decompose of water on TiO₂ electrode for the first time,TiO₂ was widely used in photo-decomposion of water,nitride and some organic pollutions and sterilization and deodorization and surface self cleaning,etc.Researchers were engaged in elucidating the process and enhancing the catalytic efficiency of TiO₂,and the friendly heterogeneous catalysis of TiO₂ plays an important part in harmonious development of human society.This thesis mainly focuses on the study of low dimensional TiO₂ with different appearances,summarized as follows:1.Used hydrothermal method to synthesis B-doped nano-TiO₂ with visible light response,and B atoms existed as B-O-Ti.The as-synthesized B-TiO₂ shows high activity in photo-decompose of nitride and phenol.Samples synthesized at 180℃for 12h shows the highest activity in nitride-decompose(5h,nitride conversion 96.7%,N₂ selectivity 88%) and phenol-decompose(5 h,conversion 100%).2.N-doped TiO₂ and titanate nanotubes were used as precursor of N-doped TiO₂ nanotubes synyhesis.As characterized,N-doped TiO₂ nanotubes synthesized by both two methods show high visible light response,and N atoms were doped successfully into TiO₂ nanotubes.Structure of nanotubes synthesized from the first method is titanate,but the structure of nanotubes synthesized from the later method is anatase TiO₂;the later one shows the most highest activity in degradation of methyl orange.3.Using metal,N-codoped TiO₂ or metal-doped titanate nanotubes as precursor, synthesized metal,N-codoped TiO₂ nanotubes.It is confirmed that nanotube synthesized from the first method is composed of titanate and the later one is composed of anatase TiO₂.After the codoping of metal and N,both nanotubes show obvious visible light response and photocatalytic acivity.Among all the nanotubes,W,N-codoped TiO₂ nanotube shows the best photocatalytic activity which synthesized by nitride under NH₃ gas flow.4.Firstly used titanate nanowire as precursor,nitridated it at different temperatures and obtained N-doped TiO₂ nanowires with layered structure.It is obvious that N doping and transformation of titanate to anatase TiO₂ could be combined in one step under appropriate nitridation temperature.After nitridation at suitable temperature,figure of nanowire reserved,and N was doped successfully.Visible light response and photocatalytic activity were obtained under N-doped TiO₂ nanowire.5.Firstly synthesized metal-doped titanate nanowire with layered structure using metal doped TiO₂ as precursor,the distance between two layers is about 0.6 nm. After nitridation under NH₃ gas flow for 2 h,titanate turned into anantase TiO₂, and obtained metal,N-codoped TiO₂ nanwire with visible light response and photocatalytic activity.