Au掺杂锐钛矿TiO2的光吸收能力第一性原理计算

STUDY ON THE FIRST PRINCIPLE OF LIGHT ABSORPTION CAPACITY OF ANATASE TiO2 DOPED WITH Au

TiO2作为光催化材料由于其带隙较大只能吸收380 nm以下的近紫外光,为了令锐钛矿TiO2更广泛应用于光催化领域中,需要对锐钛矿进行改进来增强其光吸强度甚至增加其对可见光的吸收能力.采用基于密度泛函理论框架下的第一性原理平面波赝势方法,通过Au原子替换TiO2的钛原子获得Ti1-mAumO2材料计算模型,使用Material studio8.0中的CASTEP模块对Au掺杂锐钛矿TiO2进行第一性原理计算,讨论了Au掺杂对锐钛矿晶体能隙、态密度、光吸收京数等方面的影响.结果显示,Au掺杂可以使晶体的禁带宽度减小,并且使TiO2的光吸收系数阈值发生红移,增强了光吸收的能力,在可见光区表现出一定程度的吸收.

As a photocatalytic material,TiO2 can only absorb near-ultraviolet light below 380 nm due to its large band gap.In order to make anatase TiO2 more widely used in the field of photocatalysis,it is necessary to improve anatase to enhance its light absorption intensity and even increase its ability to absorb visible light.Here,density functional theory within the framework of the first principles of plane wave pseudopotential method implemented in Material Studio 8.0 CASTEP module is employed.Ti1-mAumO2 model is obtained by replacing Ti atoms by Au atoms and then properties of the Au doping of anatase TiO2 is calculated.The effects of Au doping on bandgap,density of states,and the light absorption curve of anatase crystal is discussed.The result shows that Au doping can reduce the gap width of crystal and cause red shift of TiO2's light absorption coefficient threshold,enhancing the ability of light absorption and showing a certain degree of absorption in the visible region.In conclusion,this study has certain guiding significance to improve the application of water and light degradation of pollution.