Chlorine Adsorption on TiO2(110)/Water Interface: Nonadiabatic Molecular Dynamics Simulations for Photocatalytic Water Splitting

Abstract

Chloride is one of the most abundant ions in sea water, which is more available than fresh water. Due to lack of H2O adsorbate states near the valence band maximum (VBM) edge, the difficulty of water dissociation incidents has been reported on the rutile TiO2 surface as the excitation energy is around the band gap energy of TiO2. It is interesting whether the extra chloride can be a benefit to the water dissociation or not. In this study, the models of chlorine adatoms placed on the rutile TiO2 (110)/water interface are constructed using ab initio methods. The time-dependent spatial charges, bond-lengths of water molecules, and Hirshfeld charges are calculated by real-time time-dependent density functional theory and the Ehrenfest dynamics theory for investigating the excited state nonadiabatic dynamics of water dissociation. This study presents two photoinduced water-splitting pathways related to chlorine and analyzes the photogenerated hole along the reactions. The first step of water dissociation relies on the localized competition of oxygen charges between the dissociated water and the bridge site of TiO2 for transforming the water into hydroxyl and hydrogen by photoinduced driving force.

Excited State Calculations of Cu-Doped Anatase TiO2 (101) and (001) Nanofilms

“…When the Hubbard U parameter for titanium d-orbitals U Ti(d) = 4.2 eV is incorporated, the resulting optical absorption spectrum shows a red shift compared to neglect of the Hubbard correction. Interestingly, despite these adjustments, our analysis reveals that there is no significant difference in the absorption characteristics between the TiO 2 surfaces with and without the Hubbard correction [23,62,63]. This finding suggests that the Hubbard correction does not markedly alter the absorption properties of these surfaces, at least within the range of our study.…”

Density functional theory for doped TiO2: current research strategies and advancements

“…Summarizing this subsection, we observed that the majority of recent studies on doped TiO 2 have found the accuracy of optical property calculations conducted using several DFT-based computational techniques to be satisfactory. However, a few exceptions exist where more advanced techniques such as TDDFT, GW, or BSE methods were also employed [184,185]. These preferences indicate that despite its acknowledged limitations in describing optical properties, DFT still contributes to exploratory research.…”

Exciton states of titanium dioxide nanocrystals

“…Nanocrystalline titanium dioxide (TiO 2 ) has many applications due to its optical, thermal, photocatalytic, and electrophysical properties [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For instance, nanocrystalline TiO 2 is utilized in dye-sensitized solar cells, hydrogen production and storage processes, sensors, rechargeable batteries, self-cleaning and antibacterial surfaces.…”

“…Currently, the most active research is related to the photocatalytic activity of TiO 2 nanoparticles for the environmental cleanup of organic pollutants. Due to the chemical stability, non-toxicity, and low cost TiO 2 is considered the most promising photocatalytic for the degradation of pollutants in water and in air [1][2][3][4][9][10][11][12]15]. Titanium dioxide has three naturally occurring polymorphs: rutile, anatase with the tetragonal crystal lattice, and brookite with the orthorhombic crystal lattice [16][17][18].…”

“…In [15], the models of chlorine adatoms placed on the rutile TiO 2 (110)/water interface were constructed using ab initio methods. The time-dependent spatial charges, bond-lengths of water molecules, and Hirshfeld charges were calculated by real-time -time-dependent density functional theory and the Ehrenfest dynamics theory for investigating the excited state nonadiabatic dynamics of water dissociation.…”