Anatase TiO₂ Single Crystals Exposed with High-Reactive {111} Facets Toward Efficient H₂ Evolution

Abstract

In this study, for the first time, {111} facet exposed anatase TiO2 single crystals are prepared via both F– and ammonia as the capping reagents. In comparison with the most investigated {001}, {010}, and {101} facets for anatase TiO2, the density functional theory (DFT) calculations predict that {111} facet owns a much higher surface energy of 1.61 J/m2, which is partially attributed to the large percentage of undercoordinated Ti atoms and O atoms existed on the {111} surface. These undercoordinated atoms can act as active sites in the photoreaction. Experimentally, it is revealed that this material exhibits the superior electronic band structure which can produce more reductive electrons in the photocatalytic reaction than those of the TiO2 samples exposed with majority {010}, {101}, and {001} facets. More importantly, we demonstrate that this material is an excellent photocatalyst with much higher photocatalytic activity (405.2 μmol h–1), about 5, 9, and 13 times that of the TiO2 sample exposed with dominant {010}, {101}, and {001} facets, respectively. Both the superior surface atomic structure and electronic band structure significantly contribute to the enhanced photocatalytic activity. This work exemplifies that the surface engineering of semiconductors is one of the most effective strategies to achieve advanced and excellent performance over photofunctional materials for solar energy conversion.

Synthesis, Characterization, and Application of TiO2 Nanoparticles – Effect of pH Adjusted Solvent

“…The ESR measurements provided evidence for the presence of Ti 3+ within all the samples, and the magnetic measurements showed that the TB400 sample has a greater saturation n magnetization due to larger amounts of unpaired electrons and hence more Ti 3+ . This correlates well with the dispersive surface energy, where recent reports in the literature have shown that larger surface energy values are due to under-coordinated Ti sites on the surface of the particles (40). The photo-catalysts generate electron hole pairs when excited by UV-Vis radiation, and these eventually form OH or oxygen radicals on the surface of the particles (41).…”

Solid-base loaded WO3 photocatalyst for decomposition of harmful organics under visible light irradiation

“…This shift may be derived from changes of the amounts of functional groups, such as OH group and adsorbed water. 26,27 A similar phenomenon was also observed for NaOH-loaded WO 3 . 20 The absorption of the mixture is sum of the absorption of WO 3 and NaBiO 3 .…”

Precipitation of spherical boehmite from concentrated sodium aluminate solution by adding gibbsite as seed

“…A plane-wave cutoff energy of 300 eV was used in the calculations, which ensured a total-energy convergence of 10 − 4 eV/atom. The surface energy was calculated according to the following equation [30]:…”