Ma Xiangchao, Dai Ying, Wei Wei, Huang Baibiao, Whangbo Myung-Hwan
†School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People's Republic of China.
‡Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States.
J Phys Chem Lett. 2015 May 21;6(10):1876-82. doi: 10.1021/acs.jpclett.5b00595. Epub 2015 May 6.
The stability of both the pure and fluorine (F)-adsorbed surface of TiO2 is examined on the basis of density functional calculations. For pure surfaces, both the beneficial local geometric structures and local potential strengthen the Ti-O binding in (101), rendering it the most stable surface. For F-adsorbed surfaces, F-adsorption significantly weakens the Ti-O bonds in (101) but strengthens them in (001), so that (001) becomes more stable than (101) for the F-adsorbed surfaces. On the basis of this observation, we further show that the n-type doping in TiO2 can significantly decrease the ability of F-adsorption in switching the relative stability of the two surfaces. The present work not only provides new insights into the physical and chemical properties about both pure and F-adsorbed surfaces of TiO2 and conclusively explains related experimental results but also suggests viable ways to prepare TiO2 samples with a high percentage of (001).
基于密度泛函计算，研究了纯二氧化钛（TiO₂）表面和氟（F）吸附的TiO₂表面的稳定性。对于纯表面，有利的局部几何结构和局部势都增强了（101）面中Ti - O键的结合，使其成为最稳定的表面。对于F吸附的表面，F吸附显著削弱了（101）面中的Ti - O键，但增强了（001）面中的Ti - O键，因此对于F吸附的表面，（001）面变得比（101）面更稳定。基于这一观察结果，我们进一步表明，TiO₂中的n型掺杂可以显著降低F吸附改变两个表面相对稳定性的能力。本工作不仅为TiO₂的纯表面和F吸附表面的物理化学性质提供了新的见解，并最终解释了相关的实验结果，还提出了制备高比例（001）面TiO₂样品的可行方法。
