Rutile, anatase, brookite and titania thin film from Hubbard corrected and hybrid DFT

Abstract

As a benchmark, the structural, electronic and optical properties of the three main phases of TiO$\rm{_{2}}$ crystals have been calculated using Hubbard U correction and hybrid functional methods in density-functional theory. These calculations are compared concerning the available experimental observations on pristine TiO$\rm{_{2}}$ crystals. Modified hybrid functionals, particularly the PBE0 functional with 11.4\% fraction of exact exchange, are shown to provide highly accurate atomic structures and also accurate electronic structure data, including optical excitation energies. With $\rm{DFT+U}$, accurate optical spectra are also possible, but only if the Hubbard U is applied on the O $\rm{2p}$ electrons exclusively. Furthermore, both methods, the 11.4\%-PBE0 hybrid functional and the $\rm{DFT+U_p}$ scheme have been used to study TiO$\rm{_{2}}$ amorphous ultra-thin films, confirming the agreement of the two methods even with respect to small details of the optical spectra. Our results show that the proposed $\rm{DFT+U_p}$ methodology is computationally efficient, but still accurate. It can be applied to well-ordered TiO$\rm{_{2}}$ polymorphs as well as to amorphous TiO$\rm{_{2}}$ and will allow for the calculations of complex titania-based structures.

Black brookite rich in oxygen vacancies as an active photocatalyst for CO2 conversion: Experiments and first-principles calculations

“…The bandgap of 3.22 eV calculated for the pristine structure coincides with the measured value in Fig. 9b and with data reported in the literature [50][51][52].…”

Dual-defected pine-needle W18O49–TiO2(R)–TiO2(A) heterojunctions for the complete elimination of naphthalene

“…47 The molar percentage of TiO 2 (R) obtained by the empirical formula further proved the crystal microstructure distortion owing to the surface defects. 48 The actual molar ratio of tungsten to titanium species in the WTNWs samples can be reached with about 80.0% feed ratio, further proving the successful incorporation of tungsten species.…”

In Silico Guided Design of Metal/Semiconductor Photocatalysts: A Case of Cu-Modified TiO2 for Ciprofloxacin Degradation

“…DFT calculations represent an efficient tool not only for the prediction of behavior of metal/semiconductor interfaces but also for the explanation of their structural and electronic properties up to the level of a single atom [ 20 , 21 , 22 , 23 , 24 ]. The ongoing development of catalytic descriptors [ 25 ] and calculation procedures to overcome present methodological drawbacks [ 26 ] widens the possibility to employ in silico experiments in the design of catalyst materials. However, despite extensive research, to our knowledge, there is still a lack of systematic studies that investigate metal thin layer formation and behavior on semiconductor surfaces.…”