Regulating Photocatalytic Selectivity of Anatase TiO₂ with {101}, {001}, and {111} Facets

Abstract

In this work, we demonstrate a novel approach to control the photocatalytic selectivity of TiO 2 though different dominant crystal facets. {101}, {111}, and {001} facets exposed nanoscale anatase TiO 2 were obtained by a simple hydrothermal route with different ratio of NH 4 + and F -, then a calcined progress to clear surface adsorbent atoms. Results reveal that {101} exposed TiO 2 has some remain binding N with a mode of unsaturated N 3c exhibits selectively photocatalytic degradation of methylene orange (MO) in a methylene blue (MB) and methyl orange (MO) mixed solution, whereas TiO 2 with exposed {111} and {001} facets exhibits photocatalytic selectivity for MB. The {111} facets of anatase TiO 2 exhibit a better photocatalytic selective ability than {001} facets. It confirms that the photocatalytic selectivity can be affected by different dominant crystal facets. In a deeper analysis, there are many unsaturated O 2c on the surface of {001} and {111} facets, which enhances adsorbent selectivity and relevant photocatalytic activity of MB, at the same time, the unsaturated O 2c on the surface of {111} facets is much more than that on the surface of {001} facets results in a better photocatalytic selectivity of {111} facets. This research hopes that developing a new strategy for photocatalytic selectivity and providing a deeper understanding of different crystal facets of TiO 2 .

Facile Synthesis of BiOBr/Bi2Sn2O7 Heterojunction Photocatalysts with Improved Photocatalytic Activities

“…Since Fujishima demonstrated the photocatalysis with TiO 2 under UV‐light irradiation in 1970s, semiconductor‐based photocatalytic technique has been considered to be one of the reliable and ultimate solutions to dealing with global environmental pollution . TiO 2 is a famous semiconductor owning improved photocatalytic activities for the oxidative degradation of organic compounds . However, TiO 2 with band gap of 3.2 eV has poor nature solar efficiency and slow reaction rate, which hinders its further applications .…”

“…However, the poor light absorption and the rapid recombination of photogenerated electrons and holes still limit its photocatalytic efficiency and the practical applications . It has been proved that the construction of heterojunction through combination of two semiconductors is a promising technique to broaden responsive spectrum and suppress the charge recombination …”

“…[4][5][6] TiO 2 is a famous semiconductor owning improved photocatalytic activities for the oxidative degradation of organic compounds. 7,8 However, TiO 2 with band gap of 3.2 eV has poor nature solar efficiency and slow reaction rate, which hinders its further applications. 9,10 Thus, in order to utilize abundant and clean solar energy, the research and development of visible light responsive photocatalysts has become an appealing challenge.…”

“…24 It has been proved that the construction of heterojunction through combination of two semiconductors is a promising technique to broaden responsive spectrum and suppress the charge recombination. 8,[25][26][27] On the basis of the alignment of the valence bands and conduction bands of BiOBr and Bi 2 Sn 2 O 7 , BiOBr/Bi 2 Sn 2 O 7 is expected to exhibit enhanced photocatalytic performance. 28 In this work, we synthesized a series of BiOBr/Bi 2 Sn 2 O 7 composites by facially treating Bi 2 Sn 2 O 7 with hydrobromic acid (HBr) solution.…”

Recent progress in magnetic iron oxide–semiconductor composite nanomaterials as promising photocatalysts

“…[6] The high oxidization potential energy of OH radicals can induce many backward reactions, such as oxidizing the intermediates and products converted from the as-adsorbed CO 2 . [7,8] 4The photocatalytic treatment of high concentration organic pollutants from industrial waste poisons the photocatalyst resulting deactivation. In addition, it is difficult to separate a pure semiconductor oxide photocatalyst from the waste water treating system, [9] which further deactivates the photocatalysts.…”