Tong Xiao, Price Scott P, Robins Jeremy C, Ridge Claron, Kim Hyun You, Kemper Paul, Metiu Horia, Bowers Michael T, Buratto Steven K
Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106-9510, United States.
J Phys Chem C Nanomater Interfaces. 2022 Oct 27;126(42):17975-17982. doi: 10.1021/acs.jpcc.2c06202. Epub 2022 Oct 18.
We probe the adsorption of molecular HO on a TiO (110)-(1 × 1) surface decorated with isolated VO clusters using ultrahigh-vacuum scanning tunneling microscopy (UHV-STM) and temperature-programmed desorption (TPD). Our STM images show that preadsorbed VO clusters on the TiO (110)-(1 × 1) surface induce the adsorption of HO molecules at room temperature (RT). The adsorbed HO molecules form strings of beads of HO dimers bound to the 5-fold coordinated Ti atom (5c-Ti) rows and are anchored by VO. This RT adsorption is completely reversible and is unique to the VO-decorated TiO surface. TPD spectra reveal two new desorption states for VO stabilized HO at 395 and 445 K, which is in sharp contrast to the desorption of water due to recombination of hydroxyl groups at 490 K from clean TiO(110)-(1 × 1) surfaces. Density functional theory (DFT) calculations show that the binding energy of molecular HO to the VO clusters on the TiO (110)-(1 × 1) surface is higher than binding to the bare surface by 0.42 eV, and the resulting HO-VO-TiO (110) complex provides the anchor point for adsorption of the string of beads of HO dimers.
我们使用超高真空扫描隧道显微镜（UHV-STM）和程序升温脱附（TPD）来探究分子HO在装饰有孤立VO团簇的TiO(110)-(1×1)表面上的吸附情况。我们的STM图像显示，TiO(110)-(1×1)表面上预先吸附的VO团簇在室温（RT）下会诱导HO分子的吸附。吸附的HO分子形成与五重配位Ti原子（5c-Ti）行结合的HO二聚体串珠，并由VO固定。这种室温吸附是完全可逆的，并且是VO修饰的TiO表面所特有的。TPD光谱揭示了VO稳定的HO在395和445 K时有两种新的脱附状态，这与清洁TiO(110)-(1×1)表面上由于羟基重组在490 K时水的脱附形成鲜明对比。密度泛函理论（DFT）计算表明，分子HO与TiO(110)-(1×1)表面上的VO团簇的结合能比与裸表面的结合能高0.42 eV，并且由此产生的HO-VO-TiO(110)复合物为HO二聚体串珠的吸附提供了锚定点。
