Pan Hui, Gu Baohua, Zhang Zhenyu
Environmental Science Division, Material Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, and Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996.
J Chem Theory Comput. 2009 Nov 10;5(11):3074-8. doi: 10.1021/ct9002724.
The electronic properties of defected TiO2 were investigated using the first-principles calculations based on density functional theory and generalized gradient approximation. Three typical defects, oxygen vacancy, titanium interstitial, and titanium vacancy, were considered in three TiO2 polymorphs, anatase, rutile, and brookite, respectively. Our calculations demonstrated that the defect band is formed by removing an oxygen atom from or inserting an interstitial Ti atom into the TiO2 lattice, which is responsible for the improvement of photocatalytic ability due to the enhanced visible-light absorption. Our calculations further revealed that the defect formation energy increases as following brookite, anatase, and rutile, indicating that defects are easy to be created in brookite TiO2. The relatively high defect density and wide defect band contribute to the better photocatalytic performance of brookite TiO2 in visible light.
基于密度泛函理论和广义梯度近似，采用第一性原理计算方法研究了缺陷TiO₂的电子性质。分别在锐钛矿、金红石和板钛矿三种TiO₂多晶型物中考虑了三种典型缺陷，即氧空位、钛间隙原子和钛空位。我们的计算表明，缺陷带是通过从TiO₂晶格中移除一个氧原子或插入一个间隙Ti原子而形成的，这由于增强的可见光吸收而导致光催化能力的提高。我们的计算进一步表明，缺陷形成能按照板钛矿、锐钛矿和金红石的顺序增加，这表明在板钛矿TiO₂中容易产生缺陷。相对较高的缺陷密度和较宽的缺陷带有助于板钛矿TiO₂在可见光下具有更好的光催化性能。
