Preparation,Modification and Photocatalytic Properties of Black TiO2 Nanomaterials

Author:Zhang Zhen

Supervisor:tan xin

Database:Doctor

Degree Year:2017

Download:101

Pages:121

Size:5834K

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Titanium dioxide has been a hot research object in the field of photocatalysis,which has excellent performances in photocatalytic degradation of organic pollutants and photolysis of water.However,there are two main drawbacks of titanium dioxide:the low utilization rate of visible light and the high recombination rate of photogenerated carriers.Black titanium dioxide has excellent absorption of visible liaght.In this paper,Black titanium dioxide was prepared by anodic oxidation and hydrothermal methods.The photocatalytic activity of Black titanium dioxide was further improved by constructing heterojunctions and introducing co-catalyst.The main research results can be summarized as follows:(1)Black titanium dioxide nanotube arrayswere synthesized via a two-step anodization procedure by controlling the duration of anodization.The microstructure of the nanomaterials was an ordered array of anatase Black titanium dioxide nanotubes with surface defects.There are some surface defects in Black nanotube arrays because of insufficient oxygen atmosphere in the sintering process.It is these surface defects that are benefit to the separation of photogenerated carriers,thereby enhancing the utilization of photogenerated carriers.It is proved that the oxygen vacancy characteristic peak signals increase with the duration of anodic oxidation time by electron paramagnetic resonance(EPR).(2)On the basis of the work of Black titanium dioxide nanotubes,a small amount of Sr(OH)2·8H2O,Cr(NO3)3·9H2O was added to Black nanotube arrays to obtain Cr-doped strontium titanate Black titanium dioxide heterojunction.The Black Cr-SrTiO3/TiO2 nanotubes with heterojunction structure were fabricated by simply controlling various hydrothermal reaction time.Black titanium dioxide has excellent visible light response performance due to surface lattice defects that is oxygen vacancies which make the formation of the tail state.In order to further improve its electron separation efficiency,Cr ions are incorporated.The excellent visible response of Black titanium dioxide and the synergistic effect of Cr-SrTiO3heterojunctions can effectively enhance the photocatalytic performance of the prepared catalysts and enhance the separation efficiency of photogenerated carriers.(3)we use the hydrothermal method to synthesize the Black titanium dioxide nanobelts,and use MoS2 as the co-catalyst,constructing the 3D structural heterojunction.MoS2/TiO2 complexes have better catalytic performance compared to pristine titanium dioxide in hydrogen production by photolysis water.MoS2 can improve the photocatalytic performance because MoS2 exposes active S atoms and forms strong bonds with H in solution.