Zhang Z, Bondarchuk O, Kay Bruce D, White J M, Dohnalek Z
Department of Chemistry and Biochemistry, Center for Materials Chemistry, University of Texas at Austin, Texas 78712, USA.
J Phys Chem B. 2006 Nov 2;110(43):21840-5. doi: 10.1021/jp063619h.
Identical regions of partially reduced TiO2(110) surfaces with bridge-bonded oxygen vacancy (BBO(V)) concentrations of approximately 10% ML (1 ML = 5.2 x 10(14) cm(-2)) were imaged using scanning tunneling microscopy (STM) before and after dosing H2O at ambient temperature (approximately 300 K). Atomically resolved images confirm that H2O adsorbs dissociatively on the BBO(V) sites, producing two hydroxyl species, one positioned at BBO(V) and denoted OH(V) and the other, denoted OH(B), formed by protonation at either of the two nearest-neighbor bridge-bonded oxygen atoms. Hydrogen hopping along the [001] direction is observed at ambient temperature, with a strong preference for OH(B) (approximately 10x) hydrogen motion. This powerful imbalance demonstrates the inequality of OH(V) and OH(B) and suggests differences in their charge and/or binding configuration.
使用扫描隧道显微镜（STM）对具有约10%单层（1单层 = 5.2×10¹⁴ cm⁻²）桥连氧空位（BBO(V)）浓度的部分还原TiO₂(110)表面的相同区域在室温（约300 K）下注入H₂O之前和之后进行成像。原子分辨图像证实，H₂O在BBO(V)位点上发生解离吸附，产生两种羟基物种，一种位于BBO(V)处，记为OH(V)，另一种记为OH(B)，是由两个最近邻桥连氧原子之一的质子化形成的。在室温下观察到氢沿[001]方向跳跃，强烈倾向于OH(B)（约10倍）的氢运动。这种强烈的不平衡表明了OH(V)和OH(B)的不平等，并暗示了它们电荷和/或结合构型的差异。
