Preparation Of Supported Gold Nanorods With Localized Surface Plasmon Resonance Effect For Regulating Photocatalytic Aromatic Amines Coupling

As a green synthesis strategy,the utilization of clean and abundant solar energy f or organic synthesis has received extensive attention.Since the report of titanium diox ide semiconductor for photocatalyticwater splitting into hydrogen,titanium dioxide ha s attracted much attention due to its potential application in the field of photocatalysis.However,due to its wide band gap,titanium dioxide could only absorb the ultraviolet light,which only accounts for 4%of the whole solar spectrum.Therefore,in order to realize the effective utilization of the solar energy,it is of great significance to develo p the photocatalytic material with visible light and near-infrared light absorption.The nano-gold material exhibits good optical response in the visible-light range d ue to its surface plasmon resonance(LSPR)effect.The light absorption could be adju sted from visible-light to near-infrared range by changing its morphology.In addition,the nano-gold material shows good performance for catalytic organic synthesis reacti ons.In this thesis,the gold nanorods with different light response were fabricated.We loaded these gold nanorods onto the surface of Ti O₂(B)nanofibers by electrostatic a dsorption and enhanced thevisible-near infrared light adsorption via LSPR effect,in tu rn improved the photocatalytic activity for organic transformations and tuned the pro duct selectivity with light.First of all,we synthesized gold nanorods via seed growth method and tuned its a spect ratios by adjusting the experimental parameters.The adjusted LSPR longitudina l absorption of gold nanorods was obtained and the light absorption range of the photo catalyst was further controlled.Secondly,Ti O₂ nanofibers with different crystal phases were prepared through a hydrothermal-annealing process.Then we modified the Ti O₂(B)nanofiber with an an ionic surfactant to make the chemical potential more negative.HRTEM analysis show ed that uniform loaded gold nanorods could be obtained via electrostatic adsorption.Finally,the material prepared above was applied in photocatalytic aromatic amin es coupling.The influence factors on the catalytic performance of the materials,such as reaction temperature,light wavelength and solvent etc.,were investigated by chang ing the experiment parameters during photocatalytic process.We found that Ti O₂(B)s upported gold nanorods exhibited excellent activity under visible-near-infrared light(470–1100 nm)compared with pure support and supported gold nanoparticles counter parts.Furthermore,results showed that light could adjust the reaction pathway of oxid ative aromatic amines in our system,reducing oxime formation and improving imine selectivity.