Facile Tailoring of Anatase TiO₂ Morphology by Use of H₂O₂: From Microflowers with Dominant {101} Facets to Microspheres with Exposed {001} Facets

Abstract

A facile hydrothermal route employing H2O2 as structure-directing agent was explored to fabricate anatase microflowers with dominant {101} facets and anatase microspheres with exposed {001} facets. The influence of H2O2 concentration on crystal structure, morphology, and facet composition of TiO2 was investigated in detail. H2O2 plays a crucial role in determining the crystal structure, morphology, and exposed facets of TiO2. The presence of H2O2 favors the formation of anatase phase. When the concentration of H2O2 was in the range 0.7–3.3 M, anatase microflowers with dominant {101} facets were produced. In contrast, when the concentration of H2O2 was higher than 6.6 M, anatase microspheres with exposed {001} facets were formed. A mechanism was proposed to account for the influence of H2O2 on crystal structure and morphology of TiO2. Photocatalytic degradations of rhodamine B and 2,4-dichlorophenol indicated that anatase microspheres with exposed {001} facets showed much higher photocatalytic activity than anatase microflowers with dominant {101} facets.

Enlarging {110} exposed facets of anatase TiO2by the synergistic action of capping agents

“…As a result, the obtained anatase TiO 2 consists of {101} and {001} exposed facets. 23 When the F − ion is present, the surface energy of (110) surface decreases dramatically, because of the strong adsorption ability of F − ion. As the concentration of H 2 O 2 increases, the surface energy of (001) reaches the value of (101) firstly.…”

“…In the presence of H 2 O 2 and HF, the titanium in Ti(OC 3 H 7 -i) 4 would be converted into Ti-F and peroxo-titanium structures. 23 Since the main difference between TiCl 4 (or TiCl 3 ) and Ti(OC 3 H 7 -i) 4 lies in the presence/absence of chlorine ion, the enlargement of {110} facets using TiCl 3 (or TiCl 4 ) as titanium source should be ascribed to the influence of Clion. Based on the above and previous experiment results, 15,16,19,23 we summarized the influences of titanium source, H 2 O 2 , Cl − , and HF on the composition of exposed facets.…”

“…S3†, high percentage {110} facets can be obtained using TiCl 4 as titanium source, similar to the result using TiCl 3 as titanium source, implying that the valence state of titanium has no influence on the shape of TiO 2 crystals. Usually, Ti 3+ would be oxidized to Ti 4+ in the presence of excess H 2 O 2 23. However, when using Ti(OC 3 H 7 -i)…”

Synthesis and chemical modifications of in-situ grown anatase TiO2 microspheres with isotropically exposed {0 0 1} facets for superhydrophobic and self-cleaning properties

“…under acidic conditions [24,26], which would retard the hydrolysis for the Ti 3+ /Ti 4+ -containing precursors. The surface energy for {0 0 1} facets are undermined by increasing H 2 O 2 concentration due to enhanced adsorption of PTCs on the {0 0 1} surface [27]. Therefore, the slow diffusion of PTCs in the solution and subsequent hydrolysis process kinetically drives the formation of vertex-truncated octahedra containing exposed {0 0 1} facets.…”

UV–visible light-activated Au@ pre-sulphated, monodisperse TiO2 aggregates for treatment of congo red and phthalylsulfathiazole

“…Surface plasmon resonance absorption is associated with a significant enhancement of the electric near field in the vicinity of the Au nanoparticles. It was reported that the enhanced near-field could boost the excitation of electron-hole pairs in TiO 2 or other semiconductors and therefore sustaining the photochemical reaction [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. At last, the influence of the gold deposition procedure on the structural and photocatalytic properties should be considered, and this is another factor affecting the photocatalytic efficiency of the Au-TiO 2 composite.…”