First-principles study of trimethylamine adsorption on anatase TiO2 nanorod surfaces

Abstract

Titanium dioxide (TiO2) nanorods are widely employed in many energy-related applications thanks to their peculiar electronic and physicochemical properties. Here we report a periodic DFT and DFT-D study of the three most exposed surfaces of stoichiometric anatase TiO2 nanorods, i.e., (100), (001) and (101). On these surfaces, we investigated the adsorption of a tertiary amine (trimethylamine, TMA): Energetic, structural and electronic features have been characterized, paying particular attention on the effects of dispersion forces on the adsorption process. We found evidence of the formation of a coordinative bond between the molecules and the titanium site of adsorption. As expected, the inclusion of dispersion correction strongly enhances the adsorption process. Moreover, in some cases TMA adsorption introduces new electronic states at the edge of the valence band. Overall, our results provide new insights on the interactions between TiO2 nanorods and nitrogen compounds, which have many scientific and technological implications

d-Glucose Adsorption on the TiO2 Anatase (100) Surface: A Direct Comparison Between Cluster-Based and Periodic Approaches

“…Conversely, our results have underlined the importance of hydrogen bond formation in the adsorption modes, in agreement with Lunell's findings (Lundqvist et al, 2006) discussed above. Associative adsorption on (101) and (100) has been reported as the favored mechanism also by Selloni and co-workers (2010) and Triggiani et al (2015). Supported by those results, we decided not to consider D-glucose dissociative adsorption at this stage of our study.…”

“…Yu et al (2014) suggested that the (101) facet should be the reactive surface in photocatalytic reactions because it has a lower conduction band edge. Triggiani et al (2015) have pointed out that the adsorption of trimethylamine (TMA) on the (100) facet affects the overall electronic structure with newly occupied states in the TiO 2 anatase band gap, leading to new principles for the design of hybrid organic-inorganic systems composed by amine-based molecular moieties exposed on titania nanorods. Even though most adsorption studies are dedicated to the (101) surface as it represents the most thermodynamically stable lattice termination (Lazzeri et al, 2001), Triggiani et al (2015) underline the importance of considering different TiO 2 facets.…”

Comparative density functional theory and density functional tight binding study of arginine and arginine-rich cell penetrating peptide TAT adsorption on anatase TiO2

“…The SIESTA code 98 forces were below 0.02 eV/Å and stresses below 0.1 GPa (for bulk TiO 2 ), respectively. The dipole correction [101][102] in the direction normal to the surfaces was checked but found to be insignificant.…”

“…The SIESTA code 98 was used with the PBE 53 were fixed at bulk positions, and all other atoms and lattice vectors were allowed to relax until forces were below 0.02 eV/Å and stresses below 0.1 GPa (for bulk TiO 2 ), respectively. The dipole correction [101][102] in the direction normal to the surfaces was checked but found to be insignificant.…”

“…where E titania/molecule is the total energy of the bioinorganic interface system, E titania the total energy of the clean anatase (101) surface and E molecule the total energy of the isolated arginine, dipeptide or TAT molecule. A negative E ads value therefore corresponds to favored adsorption.…”