Theoretical And Experimental Studies On The Preparation Of Photocatalysts From The Controllable Crystal Plane Of Titanium Dioxide

Recently,Titanium dioxide?TiO₂?had become a hot spot in the field of semiconductor photocatalysis because of its low cost,no secondary pollution,strong oxidation and reduction ability,light resistance and chemical corrosion.In spite of the fact that TiO₂ has obtained more theoretical and experimental results,TiO₂ photocatalytic method has not been able to achieve large-scale application,the main constraints including:? TiO₂ photocatalytic quantum efficiency was not high,? TiO₂ had a low utilization ratio of visible light,which required external energy consumption.There were some limitations in the traditional synthesis methods,and the exposure ratio and growth trend of anatase TiO₂ crystal surface was not strong.The particle size was different and random,so the photocatalytic properties of?001?crystal surface could not be fully utilized.The reason was that the selective growth mechanism of TiO₂ crystal surface was not clear What's more,the traditional synthesis process was not controllable,so thatthe TiO₂ crystal surface exposure ratio and growth trend could not be fully controlled,which limited the optimal utilization of TiO₂ photocatalytic performance.Therefore,it is of great significance to improve the photocatalytic performance of TiO₂ by exploring the growth mechanism of TiO₂ crystal surface and exploring the preparation technology.In this paper,firstly the theoretical study on the photocatalytic surface of TiO₂ was carried out by theoretical calculation,and the theoretical mechanism of the growth of TiO₂ crystal surface was obtained by using surface energy,adsorption energy,density of states and band.Secondly TiO₂ photocatalyst was prepared by atomic layer deposition technique.The structure and morphology of TiO₂ films were controlled by controlling the number of cycles and the temperature of the precursors.Finally the TiO₂ films were characterized by XRD,SEM and TEM,in order to obtain controllable and efficient photocatalytic degradation catalysts.The thesis indicated that in TiO₂?001?,?010?and?101?crystal plane,?001?crystal surface energy to 1.09 J/m2 was the best photocatalytic activity.In barium titanate?BTO?crystal as the substrate,constructed the TiO₂-BTO growth model and induced growth of different crystal faces of TiO₂,?001?crystal surface with binding energy of-1.27eV,the bond length were 1.916A and 1.932A,had become the most stable growth growth model.It was found that the growth of TiO₂?001?crystal planes had different effects on the catalytic degradation.The TiO₂ photocatalyst was prepared by atomic layer deposition method.Selected the optimum parameters.The TiO₂ films were prepared on the quartz glass substrate with barium titanate as the substrate.The results of XRD,SEM and TEM characterized the samples showed that TiO₂ was successfully deposited on the substrate surface by atomic layer deposition technique,and the coating thickness increased with the increase of the number of deposition cycles.The photocatalytic degradation of methyl orange with a certain concentration was tested by the prepared TiO₂ photocatalyst.The results showed that the TiO₂ photocatalyst prepared by ALD technology can degrade organic pollutants.