The Synthesis Of Gray Titanium Dioxide By Liquid Plasma And Its Photocatalytic Performance

Titanium dioxide is considered as an ideal photocatalyst due to its low cost,non-toxic and stable performance,which is expected to be widely used in pollution treatment and new energy development.However,TiO₂ redistricted by its inherent wide bandgap just absorbs ultraviolet light,Therefore,much effort has been committed to finding effective methods to promote the visible-light absorption efficiency of titanium dioxide.Recently,many reports on synthesis of black titanium dioxide has been proposed.Black titanium oxide possesses a unique crystal amorphous core-shell structure,and there are self-doped trivalent titanium Ti³⁺and oxygen vacancy defects,which shows excellent photoactivity.Lots of preparation methods of black TiO_2-x are hydrogen reduction,aluminothermic reduction,plasma ablation,and chemical and electrochemical reduction.The color of TiO₂ gradually changes from white to gray or black as the processing time increases,and oxygen vacancies and Ti³⁺exists on the surface or inside of the material,which thus significantly increases visible-light photocatalytic performance.The existing reduction methods involve complex synthetic steps,tough experimental conditions,and much energy consumption,which prevent black titanium dioxide industrial application.A simple and effective method to synthesize titanium oxide photocatalyst with stable Ti³⁺has a promising future.In this paper,liquid plasma reduction method was used to synthesize gray TiO_2-x-x with high visible-light photocatalytic performance.It has been proved that this method can effectively improve visible-light catalytic performance,and has potential advantages in treatment of water pollution The main findings are as follows:Gray TiO_2-x was synthesized by liquid plasma reduction method.Different gray TiO_2-x was synthesized by changing discharge power.The surface morphology,lattice,particle size and electronic valence state of gray TiO_2-x synthesized under different power were completely detected by various characterization test instrumentsThe effects of plasma power on various properties of the synthesized gray TiO_2-x,such as the band gap width and defect concentration were studied.Using rhodamine B,methyl orange,phenol as photocatalyst degradation targets,degradation tests were carried out under visible light conditions,and it was proved that the synthesized gray TiO_2-x had excellent visible photocatalytic effect,and the good stability of the material was confirmed by repeated experiments.Combining the results obtained by analyzing and testing the instrument,the mechanism of the photocatalytic reaction of gray TiO_2-x-x was explained...