Synthesis of High-Quality Brookite TiO₂ Single-Crystalline Nanosheets with Specific Facets Exposed: Tuning Catalysts from Inert to Highly Reactive

Abstract

The brookite phase of TiO(2) is hardly prepared and rarely studied in comparison with the common anatase and rutile phases. In addition, there exist immense controversies over the cognition of the light-induced liveliness of this material. Here, a novel, low-basicity solution chemistry method was first used to prepare homogeneous high-quality brookite TiO(2) single-crystalline nanosheets surrounded with four {210}, two {101}, and two {201} facets. These nanosheets exhibited outstanding activity toward the catalytic degradation of organic contaminants superior even to that of Degussa P25, due to the exposure of high-energy facets and the effective suppression of recombination rates of photogenerated electrons and holes by these facets as the oxidative and reductive sites. In contrast, irregularly faceted phase-pure brookite nanoflowers and nanospindles were inactive in catalytic reactions. These results demonstrate that the photocatalytic activity of brookite TiO(2) is highly dependent upon its exposed facets, which offers a strategy for tuning the catalysts from inert to highly active through tailoring of the morphology and surface structure.

Brookite, the Least Known TiO2 Photocatalyst

“…This low value is ascribable to the presence of impurities in the mineral that was pale brown in color. On the other hand, different band gap values were obtained by varying the duration of the hydrothermal treatment [18] or the kind of nanostructure (nanosheets, nanospindles, nanoflowers) [27]. Koelsch et al [21] determined the band gap of brookite nanoparticles as 3.4 eV, measuring the optical transmission of brookite dispersions at different concentrations and by UV fluorescence measurements.…”

“…humming-top-like nanostructures titanium isopropoxide hydrothermal treatment [25] macroporous spherical nanoparticles brookite nanoparticles spray drying with colloidal templating [96] hollow nanospheres titanium-peroxo-glycolate complex deposition on spherical polystyrene and hydrothermal treatment [97] pseudo-cube shaped nanocrystals titanium-peroxo complex oleate-modified hydrothermal treatment [95] Lin et al [27] synthesized brookite nanosheets with a regularly truncated tetragonal shape through a low-basicity hydrothermal process utilizing TiCl 4 as titanium source, urea as in situ OH complex transformed into single-crystalline nanosheets with specific facets exposed.…”

One‐Pot Synthesis of Cu‐Nanocluster‐Decorated Brookite TiO2Quasi‐Nanocubes for Enhanced Activity and Selectivity of CO2 Photoreduction to CH4

“…[16] In 2012, high-qualityb rookite TiO 2 materials with various morphologies were fabricated, and the single-crystal nanosheets exhibited ab etter photodegradation activity for organic contaminants compared to other morphologies. [17] More recently,b rookite TiO 2 quasi-nanocubes (BTN) with high-phase purity were synthesized through ah ydrothermal methodi n our group. [18] When used as photoanode materials of DSSCs, significantly improved photovoltaic conversion efficiencies were obtained.…”

“…All Cu-BTN products with different Cu-loading contentse xhibit XRD patterns identical to that of pristine BTN, which can be well assigned to the brookite TiO 2 (JCPDS No. [17][18][19] No other TiO 2 crystal phase can be observed from those XRD patterns, indicating that Cu-BTN products are still brookite TiO 2 with high phase purity.M oreover,t hose diffraction peaks of Cu-BTN products show no obvious shift as compared to the pristine BTN, and no peak that can be assigned to Cu, CuO, Cu 2 Oo ro ther Cu compound is detected (even for 2.5 %C u-BTN), suggesting that the Cu species do not incorporate into the brookite lattice, and probablyd ecorate on the BTN surfaces with good dispersity andl ow loading content. Moreover,X RD Rietveld refinement results ( Figure S1 and Ta ble S1)a lso indicatet hat the lattice parameters of pristine BTN and 1.5 %C u-BTN are quite similar.…”

The Effect of Process Condition on the Structure and Optical Properties of Zn/Fe/Sn/Sb-TiO2Three Dimensional Particle-Electrode

“…Up to now, template-assisted synthetic method has been proved to be the most-applied and most-effective route to fabricate inorganic hollow structures. Titanium dioxide(TiO 2 ), as one of the most important transition-metal functional oxides, has attracted extensive attention during the past decades due to its superior physical and chemical properties and a wide variety of potential use in diverse fields such as solar energy conversion, environmental purification and water-treatment [16][17][18] .…”