Study On The Rich Surface Hydroxyl Structure Control And Photoelectric Performance Improvement Of Nano Titanium Dioxide

As one of the most widely used semiconductor materials,titanium dioxide has shown a promising prospect in the fields of photocatalysis and energy storage.Although titanium dioxide has good photocatalytic activity and stability,its application is limited by its low ion/electron conductivity and carrier transport efficiency.The nanoscale engineering design can realize the efficient material transmission,and the surface interface engineering design can significantly improve the intrinsic performance of titanium dioxide.For improving the performance of titanium dioxide,this paper which based on the nanostructure design of titanium dioxide further realizes the regulation of surface hydroxyl and interfacial vacancy in titanium dioxide.The specific contents are as follows:(1)Synthesis for nanostructure anatase titanium dioxide with rich hydroxy:The performance of titanium dioxide is improved by using the method of fluoride-containing ionic liquid treatment to nanostructure titanium dioxide with higher activity.Because of the ionic liquid is dehydrated at a high temperature,the water molecules combine with the oxygen vacancy of titanium dioxide at high temperature to form hydroxy-rich nanostructure titanium dioxide.The existence of surface hydroxyl groups is proved by ¹H TQ-SQ MAS NMR spectra.The reuse of ionic liquid is realized by recycling ionic liquid.The rich surface hydroxyl groups in nanostructure titanium dioxide significantly improve its performance in photocurrent,photocatalysis,energy storage and other aspects.The photocurrent response of titanium dioxide with rich surface hydroxyl(TiO_2-OH)is 3.3-fold of N-TiO₂.The photocatalytic performance of TiO_2-OH is 3-fold of ordinary titanium dioxide and 1.7-fold of Nano-TiO₂.Besides,TiO_2-OH also have more than 90%photocatalytic activity after five cycles of reaction.The electrochemical performance of TiO_2-OH is 1.4-fold of N-TiO₂.Finally,the mechanism of charge directed transport on the atomic/nanoscale are presented,and the controllable synthesis of hydroxyl species on the surface of titanium dioxide and the hole-trapping effect are clarified.(2)Synthesis for anatase hollow microspheres of titanium dioxide:The hollow structure of amorphous titanium dioxide microspheres is obtained by adding fluorine-containing ionic liquid on process of solvent thermal.Then calcination remove the fluorine atom and the organic group part of the ionic liquid which induces oxygen vacancy and defect mesoporous.In terms of structure characterization,the formation of hollow structure and defect mesoporous is proved by SEM and TEM.NMR,XPS and EPR proved that the ionic liquid enters into the crystal lattice during the synthesis process and increased the content of oxygen vacancy after calcining.In terms of performance,liquid and gas degradation,hydrogen production,lithium storage,lithium sulfur and photocatalytic stability in pure water and simulated seawater under light are tested.The photocatalytic performance of hollow microsphere titanium dioxide(H-TiO₂)is 2.2-fold of ordinary titanium dioxide and 1.5-fold of commercial nano titanium dioxide(Nano-TiO₂),and it also has over 90%photocatalytic activity after five cycles of reaction.The electrochemical performance is 1.7-fold of normal titanium dioxide(N-TiO₂).