阴离子掺杂TiO_2的芯位移和热力学性质的第一性原理研究(英文)

A first principles study of the energetics and core level shifts of anion-doped TiO_2 photocatalysts

采用第一性原理计算考察了阴离子(硼、碳、氮、氟、磷、硫)掺杂的二氧化钛(包括锐钛矿相和金红石相).芯位移计算结果表明,在氮掺杂的TiO2中,间隙掺杂类型的N的1能级在XPS能谱上峰的位置要比替代掺杂的能级高,类似的结果也在硼、碳、磷和硫掺杂的TiO2上发现.然而对于F掺杂的TiO2替代掺杂的峰位置比间隙掺杂的高,且与TiO2的晶相无关.还对阴离子掺杂的TiO2进行了热力学研究.结果表明,替换掺杂的形成焓高于间隙掺杂的,因此替代掺杂的TiO2的制备需要苛刻的条件,而间隙掺杂TiO2的制备只需温和的湿化学条件.

We present a comprehensive and improved density functional theory（DFT]calculation of anion-doped（anion = B,C,N,F,P,S]anatase and rutile TiO_2.The first part is a first principles calculation of the core level shifts（CLS]for various anion dopants in both anatase and rutile TiO_2.The CLS results revealed that interstitial N had a higher N 1s binding energy than substitutional N,which agreed well with experimental results.The calculation also showed that for B-,C-,S-,and P-doped TiO2,the interstitial dopant had an energy that is higher than that of a substitutional dopant,which is similar to N-doped TiO2.However,for F-doped TiO2,the energy of the substitutional dopant is higher,and this is irrespective of the TiO2 crystallography.We also calculated the enthalpy of doping and found that the substitutional dopant had a higher enthalpy than the interstitial dopant.The results revealed that substitutional doping required severe experimental conditions,whereas interstitial doping only requires modest wet chemistry conditions.