Enhanced molecular adsorption of ethylene on reduced anatase TiO₂ (001): role of surface O-vacancies

Abstract

A density functional theory (DFT)-based study of ethylene (C2H4) adsorption on a reduced anatase titanium dioxide (TiO2) (001) surface, i.e., with a surface oxygen vacancy (Ovac), is presented.

Effect of oxygen vacancy concentration on the photocatalytic hydrogen evolution performance of anatase TiO2: DFT and experimental studies

“…The convergence criteria of energy, maximum force, maximum stress, and maximum displacement are 1×10 − 5 eV/atom, 0.03 eV/Å, 0.05 GPa, and 0.001 Å, respectively. The optimized anatase TiO 2 lattice parameters are a = b = 3.79 Å and c = 9.77 Å, which are consistent with the previous experimental and theoretical results [31][32][33]. In this work, a (1 × 4) anatase (101) surface supercell was used as the slab model with three O-Ti-O layers, and the underlying O-Ti-O layer was xed to simulate the bulk atomic structure, as shown in Fig.…”

In Situ Creation of Oxygen Vacancies in Porous Bimetallic La/Zr Sorbent for Aqueous Phosphate: Hierarchical Pores Control Mass Transport and Vacancy Sites Determine Interaction

“…The nature of the adsorption is the orbital interactions between the adsorbate and solid surface, which is directly relevant to the solid surface states (the electronic structure and associated chemical properties) on sorbents. , For example, the adsorption of molecular species on metal surfaces is controlled by the location of band center, band filling, and width of metal d bands from the orbital interactions of adsorbate valence states with the surface states. , At the meantime, by increasing the number of coordinatively unsaturated metal atoms on the surface, some recent reports demonstrated that introduction of oxygen vacancy (V O ) on metal oxide surfaces could enhance the adsorption of reactive molecular species. , More importantly, the presence of suitable V O on sorbents can also balance processes of adsorption and dissociation to remove small molecules, including water, methanol, and dimethyl methylphosphonate. − However, the random V O creation approaches and elusive enhancement mechanism of the role V O in interfacial–adsorbate interaction should be the main restriction for the purpose of superior adsorption performance.…”

Relevance of Dispersion and the Electronic Spin in the DFT + U Approach for the Description of Pristine and Defective TiO2 Anatase

“…Indeed, PBE-D2 U = 3 calculations were carried out for the analysis of the defective TiO 2 (001) surface and to study the adsorption properties. 24 However, it is unclear whether this may affect the oxygen vacancy formation energy because there is an additional limiting factor that must be taken into account related to the overestimation of the oxygen-binding energy when the GGA method is used. 26 This may be considered, however, for studies on chemical reactivity in catalysis, given the relevance of the reaction energy values on determining a preferred reaction pathway.…”

“… 23 PBE-D2 + U ( U = 3) calculations have shown an accurate description of the electronic structure of reduced TiO 2 anatase using a TiO 2 (001)-2 × 2 surface model. 24 It has been reported that including both the Hubbard U and van der Waals corrections is important for describing the interactions of reactive molecules with the anatase surface. 25 …”

“…For anatase, the U values of 2.6 and 2.9 were determined using the linear response theory with PBE and PBEsol functionals, respectively, in conjunction with standard pseudopotentials . PBE-D2 + U ( U = 3) calculations have shown an accurate description of the electronic structure of reduced TiO 2 anatase using a TiO 2 (001)-2 × 2 surface model . It has been reported that including both the Hubbard U and van der Waals corrections is important for describing the interactions of reactive molecules with the anatase surface …”