Ce-N共掺锐钛矿TiO2（001）取向电子结构和光学性质

Electronic structure and optical properties of Ce-N co-doped anatase-TiO2 on （001） orientation

采用第一性原理研究了Ce和N共掺杂锐钛矿TiO2的稳定性、电子结构和光学性质.结果表明在锐钛矿TiO2中Ce倾向于间隙掺杂,而N更倾向于O替位掺杂;Ce单掺杂和Ce-N共掺杂都能使TiO2带隙宽度减小,同时N原子还能在价带顶引入浅受主能级,有利于可见光的吸收和阻止光生载流子-空穴复合;Ce单掺杂和Ce-N共掺杂锐钛矿TiO2(001)取向都满足光催化制氢条件,因此都具有良好的光催化特性.综合分析带边位置和吸收光谱发现Ce-N共掺杂能有效提高锐钛矿TiO2(001)取向的光催化制氢能力.

The stability, electronic structures and optical properties of Ce and N codoped anatase TiO2 were studied by using first principle calculations. The results suggest that Ce prefers to be doped at the interstitial sites of the TiO2, while N atom prefers to substitute O atom. Both Ce and N can reduce the band gap width of TiO2, and N produces a new shallow acceptor level on the top of valence band, which could prevent the recombination of photo-generated electron-hole pairs and improve the solar light absorption. In addition, both Ce doped and Ce-N co-doped TiO2(001) orientation satisfy the requirement of water splitting, and thus have excellent photocatalytic properties. By analyzing the band edge position and absorption spectra together, it could be found that Ce-N co-doped anatase TiO2(001) orientation could improve the photocatalytic hydrogen production capability.