Comparing Quasiparticle H2O Level Alignment on Anatase and Rutile TiO2
Knowledge of the alignment of molecular frontier levels in the ground state can be used to predict the photocatalytic activity of an interface. The position of the adsorbate’s highest occupied molecular orbital (HOMO) levels relative to the substrate’s valence band maximum (VBM) in the interface describes the favorability of photogenerated hole transfer from the VBM to the adsorbed molecule. This is a key quantity for assessing and comparing H2O photooxidation activities on two prototypical photocatalytic TiO2 surfaces: anatase (A)-TiO2(101) and rutile (R)-TiO2(110). Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) G0W0 calculations, we assess the relative photocatalytic activity of intact and dissociated H2O on coordinately unsaturated (Ticus) sites of idealized stoichiometric A-TiO2(101)/R-TiO2(110) and bridging O vacancies (Obrvac) of defective A-TiO2-x(101)/R-TiO2-x(110) surfaces (x = 1/4, 1/8) for various coverages. Such a many-body treatment is necessary to correctly describe the anisotropic screening of electron-electron interactions at a photocatalytic interface and, hence, obtain accurate interfacial level alignments. The more favorable ground state HOMO level alignment for A-TiO2(101) may explain why the anatase polymorph shows higher photocatalytic activities than the rutile polymorph. Our results indicate that (1) hole trapping is more favored on A-TiO2(101) than RTiO2(110) and (2) HO@Ticus is more photocatalytically active than intact H2O@Ticus.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1214069
- Journal Information:
- ACS Catalysis, 5(7):4242–4254, Journal Name: ACS Catalysis, 5(7):4242–4254
- Country of Publication:
- United States
- Language:
- English
Similar Records
Highly Active Rutile TiO2 Nanocrystalline Photocatalysts
Water dissociation at the water–rutile TiO 2 (110) interface from ab initio-based deep neural network simulations