Decahedral Single-Crystalline Particles of Anatase Titanium(IV) Oxide with High Photocatalytic Activity

Abstract

Decahedral single-crystalline anatase particles prepared by a newly developed gas-phase process showed photocatalytic activities superior to those of P25 photocatalyst despite their relatively smaller specific surface area compared with that of P25, probably because of the low density of particle boundaries and crystalline defects.

Decahedral-shaped anatase titania photocatalyst particles: Synthesis in a newly developed coaxial-flow gas-phase reactor

“…(a) oxidative decomposition of acetic acid (CO 2 system) and (b) dehydrogenation of methanol with in-situ platinum photodeposition under deaerated conditions (H 2 system) [17]. The commercial photocatalyst Degussa (Evonik) P25 was used as a reference sample because of its high level of activity in various photocatalytic reactions ensuring clear discussion of the influence of reaction parameters on photocatalytic activity of DAPs [40].…”

“…Decahedral-shaped anatase titania particles (DAPs) have recently been classified as a photocatalytic material with a high level of photocatalytic activity [17][18][19]. The presence of two additional (in comparison to natural anatase titania crystals of octahedral shape) square {001} facets in DAPs and their relation to {101} facets are expected to play a crucial role in the enhancement of photocatalytic efficiency for different reaction systems [20].…”

“…However, the photocatalytic activity of this material was not evaluated. Another method for producing DAPs in a gas phase was developed by our group [17][18][19]. The main idea of this method is to apply rapid heating and quenching, which may preclude formation of octahedral anatase particles, of a gas reaction mixture.…”

“…Two variants of this experimental system depending on the source of heat have been used. In one system, a quartz glass tube was rotated around the cylindrical axis for homogeneous temperature distribution and was heated by an oxyhydrogen flame burner at 1573 K [17,18]. In the other system, an infrared furnace equipped with platinum foil located in the center part of quartz glass tube was used to assure a more stable and precise temperature in the heating zone [19].…”

“…The experiments were performed in a newly developed coaxial-flow gas-phase reactor that enables a continuous and stable flow of TiCl 4 vapor to be maintained. In the previous reaction systems [17][18][19], the vapor of …”