Unique adsorption behaviors of carboxylic acids at rutile TiO2(110)

作者：Yu, Yan-Yan; Gong, Xue-Qing^*

来源：Surface Science, 2015, 641: 82-90.

DOI：10.1016/j.susc.2015.05.023

• Rutile TiO2
• Carboxylic acids
• p(2 x 1) and c(2 x 2) domains
• Surface relaxation
• Bond symmetries
• Density functional theory

The coverage-dependent adsorption behavior of acetic acid (CH3COOH) on rutile TiO2(110) was investigated by means of density functional theory (DFT) calculations, corrected by on-site Coulomb corrections and long-range dispersion interactions. The p(2 x 1) and c(2 x 2) domains of dissociatively adsorbed acetic acid under different coverages have been studied in detail regarding their structural and energetic properties. Adsorptions of formic acid (HCOOH) and carbonic acid (H2CO3) were also considered for better understanding the adsorption behaviors of carboxylic acids. Our calculation results show that carboxylic adds prefer to dissociatively adsorb in bridging bidentate configuration, and it induces significant surface relaxation at the adsorption site, which also affects other surface atoms nearby. Interestingly, we have shown that such adsorption-induced relaxations still maintain bond symmetries for surface Ti cations within the p(2 x 1) domain while they are drastically broken within the c(2 x 2) domain, giving rise to unstable Ti cations at the surface. This work not only explains the long-lasting puzzle of the preferable occurrence of p(2 x 1) domain for the adsorbed carboxylic acids at rutile TiO2(110), it also proposes a novel scheme that metal oxide surfaces may follow when they are involved in the processes like surface functionalization and self-assembly.

• 出版日期2015-11
• 单位华东理工大学