摘要:
因在温室气体的降解中扮演重要的角色,通过改性来提高二氧化钛的光催化性能的相关研究备受关注.由于催化反应主要发生在材料表面,因此对材料表面的改性研究尤为重要.本文采用第一性原理方法计算了金属Ag,Cu单掺杂及协同掺杂TiO2(001)和(101)表面不同位置,通过形成能的比较获得了最稳定的晶体结构.通过对能带及态密度的对比得出:离子掺杂(001)表面所形成的活性基团的氧化性较(101)面更强,利于光催化氧化性能的提升;表面协同掺杂较单掺杂具有更强的光响应效率,与前人的实验结果符合较好.
Abstract:
The photocatalytic properties of TiO2 improved by modifying its surface have attracted more and more attention,because they play an important role in the photocatalytic degradation of greenhouse gases.Based on the fact that the photocatalytic reactions main occur on the catalyst surface,the surface modification becomes an effective method to improve the photocatalyst properties while the reaction mechanism research can give us a clear picture about it.Using the first principle calculations,the formation energies of TiO2 are calculated with doped and codoped by Cu and Ag atoms at different positions of the (001) and (101) surfaces.Comparing the formation energies,the most stable crystal structures are obtained while the electronic structures are calculated.Based on the analysis of the band structures and the density of states of atoms,it is proved that the oxidation activity of the active group formed on the (001) surface is stronger than that on (101) surface,which is more conducive to the improvement of photocatalytic oxidation properties.Meanwhile,the TiO2 compounds codoped by bimetal on the two surfaces have better light response than doped by one species of ions,which is in good agreement with the former experimental results.
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