Solvothermal Synthesis and Photoreactivity of Anatase TiO₂ Nanosheets with Dominant {001} Facets

Abstract

Owing to wide-ranging industrial applications and fundamental importance, tailored synthesis of well-faceted single crystals of anatase TiO(2) with high percentage of reactive facets has attracted much research interest. In this work, high-quality anatase TiO(2) single-crystal nanosheets mainly dominated by {001} facets have been prepared by using a water-2-propanol solvothermal synthetic route. The synergistic functions of 2-propanol and HF on the growth of anatase TiO(2) single-crystal nanosheets were studied by first-principle theoretical calculations, revealing that the addition of 2-propanol can strengthen the stabilization effect associated with fluorine adsorption over (001) surface and thus stimulate its preferred growth. By measuring the (*)OH species with terephthalic acid scavenger, the as-prepared anatase TiO(2) single-crystal nanosheets having 64% {001} facets show superior photoreactivity (more than 5 times), compared to P25 as a benchmarking material.

Recent progress of arsenic adsorption on TiO 2 in the presence of coexisting ions: A review

“…Thus, TiO 2 with highly-active {001} facets should present a favorable adsorption to As. Although much effort has been put into fabricating TiO 2 with more exposed {001} facets, the synthesized TiO 2 exhibits a limited specific surface area of 1.6 m 2 /g (Yang et al, 2009). Thus, the synthesis of TiO 2 with more exposed active facets and large surface areas is another direction in which to endeavor.…”

Specific Facets-Dominated Anatase TiO2: Fluorine-Mediated Synthesis and Photoactivity

“…In this context, Yang et al [28] brilliantly succeeded in the synthesis of anatase TiO 2 crystals with 47% of {001} facets under hydrothermal conditions, employing HF as capping agent. They also prepared high-quality anatase TiO 2 single-crystal nanosheets (SCNSs) with 64% {001} facets, employing 2-propanol as a synergistic capping agent and reaction medium, together with HF [30]. Theoretical calculations and experimental evidence clarified the key role of 2-propanol, which acts as a protecting agent, by heterolytically dissociating under acidic conditions to form alkoxy groups ((CH 3 ) 2 CHO − ), which bind to coordinatively unsaturated Ti 4+ cations on {001} and {101} facets.…”

Photocatalytic oxidation of gaseous ammonia over fluorinated TiO2 with exposed (001) facets

“…Recently, anatase TiO 2 with exposed (0 0 1) facets has drawn great attention since Yang et al prepared anatase TiO 2 microcrystals with 47% highly reactive (0 0 1) facets [21][22][23][24][25][26][27][28][29][30]. The average surface free energy of (0 0 1) facets is 0.90 J/m 2 , which is higher than those of (1 0 0) (0.53 J/m 2 ) and (1 0 1) facets (0.44 J/m 2 ) [31].…”

“…In controllable synthesis of TiO 2 with exposed (0 0 1) facets, fluorine has been commonly used as a morphology-controlling agent to lower the surface energy in order to expose the reactive (0 0 1) facets [23,32,33]. Anatase TiO 2 with a high percentage of the reactive (0 0 1) facets has exhibited excellent photoreactivity, even much better than pure anatase TiO 2 or commercial P25 in photocatalytic reactions, such the oxidation of acetone [23], OH radical generation [24] and the degradation of methylene orange (MO) [34] and methylene blue (MB) [35], etc. However, it is also reported that, compared with the other two facets, (0 0 1) facets are not always more reactive for some reactions, such as the reaction of hydrogen generation under UV light irradiation [36,37].…”