Formation of new crystal faces on TiO2 particles by treatment with aqueous HF solution or hot sulfuric acid

The origin of photochemical anisotropy in SrTiO3

“…If this subset of sites does not include those needed for both half reactions, the planar specimen may exhibit a reduced reactivity with respect to a surface with the same orientation on a microcrystal bounded by several different planes. This difference might contribute to the apparent contradiction between the results of experiments on planar TiO 2 samples and TiO 2 microcrystals [1,2,5].…”

“…In other words, they occur at different rates on surfaces with different orientations. Furthermore, it has been observed that some surface orientations can promote the oxidation half of the reaction while another promotes the reduction half reaction [2,4]. While the mechanisms behind this phenomenon are not well understood, it is potentially important for the design of photocatalysts.…”

“…Photochemical reactions on metal oxides are anisotropic [1][2][3]. In other words, they occur at different rates on surfaces with different orientations.…”

Tuning TiO2nanoparticle morphology in graphene–TiO2hybrids by graphene surface modification

“…17 This morphology can be changed by synthesizing anatase NPs in the presence of specific shape controllers. 12,[18][19][20] A first breakthrough was achieved by Lu et al, 21,22 who synthesized TiO 2 NPs with a very high percentage of exposed {001} facets using hydrofluoric acid; such particles showed excellent photocatalytic activity. Most of the shape controllers used in TiO 2 synthesis have amino and carboxylic groups in their structure, since these functionalities are known to interact with TiO 2 facets.…”

“…[7][8][9] In most of these applications, not only the phase and size of TiO 2 NPs, but also their shape and the extent to which different facets are developed determine the NP activity. [10][11][12] For example, while the {101} facets are the most thermodynamically stable in TiO 2 anatase, the {001} facets are often preferred due to their higher reactivity 13 and higher oxidating ability. 14,15 Anatase crystals found in nature have a tetragonal bipyramidal shape, often truncated, which exposes eight equivalent {101} facets and two equivalent {001} facets (Fig.…”