Synthesis of [111]- and {010}-faceted anatase TiO₂ nanocrystals from tri-titanate nanosheets and their photocatalytic and DSSC performances

Abstract

[111]- and {010}-faceted anatase nanocrystals with controllable crystal size and morphology were synthesized from tri-titanate H2Ti3O7 nanosheets by hydrothermal reaction. The nanostructures and the formation reaction mechanism of the obtained TiO2 nanocrystals were investigated using XRD, FE-SEM, and TEM. Furthermore, the photocatalytic and dye-sensitized solar cell (DSSC) performances of the synthesized anatase nanocrystals were also characterized. Two types of reactions occur in the formation process of the anatase nanocrystals. One is an in situ topochemical conversion reaction of the layered titanate structure to an anatase structure, and another is the dissolution-deposition reaction on the particle surface, which splits the formed nanosheet-like particles into small TiO2 nanocrystals. The surface photocatalytic activity and the DSSC performance of the anatase nanocrystals are dependent on the crystal facet exposed on the particle surface, which increases in the order of non-facet < [111]-facet < {010}-facet. The increasing order corresponds to the increasing order of the bandgap and energy level of the lowest valence band of the anatase nanocrystals. Furthermore, the facet of the anatase also affects the DSSC performance, which is enhanced in the order of non-facet < [111]-facet < {010}-facet.

Synthesis, Transformation Mechanism and Photocatalytic Properties of Various Morphologies Anatase TiO2 Nanocrystals Derived From Tetratitanate Nanobelts

“…The tetratitanate nanobelts can be transformed the mixed‐phase of anatase/brookite when the pH value beyond 13.0. The result is different from hydrothermal treatment of other titanate nanobelts, in which single‐phase rutile is formed within the range of pH below 1.0 …”

“…Chen et al . also prepared nanoleaf‐like anatase TiO 2 nanocrystals with exposed {010} facets by using tri‐titanate H 2 Ti 3 O 7 nanosheets as the precursor under hydrothermal conditions, which exhibited higher photocatalytic performance for the degradation of methylene blue . We prepared short and long spindle‐shaped anatase TiO 2 nanocrystals with a large percentage of {010} facets (81.9%∼96.9%) by using rock‐salt‐structured H 2 TiO 3 nanosheets as the precursor at different pH values under hydrothermal conditions, which showed excellent photocatalytic activity compared to the benchmark P25 TiO 2 nanocrystals .…”

Ordered Single-Crystalline Anatase TiO2Nanorod Clusters Planted on Graphene for Fast Charge Transfer in Photoelectrochemical Solar Cells

“…Apparently, based on continuous lattice fringes, each individual nanorod is likely to be single crystal. Two sets of lattice fringes with interplane spacing of 0.24 and 0.35 nm indicated in Figure d are attributed to (001) and (101) planes of the anatase phase, respectively, while the angle value of 68.3° corresponds to the angle between (101) and (001) facets . Interestingly, the longitudinal axis of the nanorod is parallel to the lattice fringe of (101) plane.…”

Cu-doped TiO2/reduced graphene oxide thin-film photocatalysts: Effect of Cu content upon methylene blue removal in water

“…Inset of Fig. 3c shows 2-D fast Fourier transformation (FFT) of selected nanocrystals, which represents a lattice ϳ structure with d (200) = d (020) = 0.19 nm, Ě ;ϭĎϯͿ = 0.15nm and d (111) = 0.22 nm corresponding to anatase crystal structure [22,23]. This result demonstrated the successful formation of anatase crystalline structure.…”