Anatase TiO2 Single Crystals Exposed with High-Reactive {111} Facets Toward Efficient H2 Evolution
نویسندگان
چکیده
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/m, 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.
منابع مشابه
Anatase TiO2 crystals with exposed high-index facets.
Put your best face forward: The performance of TiO2 anatase crystals in energy and environmental applications is normally correlated with the TiO2 crystal facets exposed, and increasing the percentage of highly reactive surfaces is extremely important. A new gas-phase oxidation process using TiCl4 as precursor now yields anatase TiO2 single crystals with primarily high-index {105} facets, which...
متن کاملSynthesis of nano-sized anatase TiO2 with reactive {001} facets using lamellar protonated titanate as precursor.
Nano-sized anatase TiO(2) with exposed {001} facets was synthesized from lamellar protonated titanate precursor. Owing to small size (ca. 11 nm) and high surface area (155 m(2) g(-1)), the crystals with 26.1% {001} facets exhibited markedly superior photoactivity to reference ca. 76 nm anatase TiO(2) nanosheets with 88.4% {001} facets.
متن کاملLow-temperature synthesis of high-ordered anatase TiO2 nanotube array films coated with exposed {001} nanofacets
High-ordered anatase TiO2 nanotube array films coated with exposed high-reactive {001} nanofacets were fabricated by a modified hydrothermal method using amorphous anodic TiO2 nanotube arrays (ATONAs) as starting materials. It was found that the reaction between gas phase HF and solid ATONAs played a key role in the transformation process from amorphous to anatase TiO2, and the TiO2 tubular str...
متن کاملAnatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells
Anatase TiO2 nanoparticles with exposed {001} facets were synthesized from Ti powder via a sequential hydrothermal reaction process. At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution. If the second-step hydrotherma...
متن کامل