Dependence of Quenching Process on the Photocatalytic Activity of Solvothermal-Derived TiO₂ with Various Crystallite Sizes

Abstract

In the present work, the effect of quenching on surface defect and photocatalytic activity of the solvothermal-derived nanocrystalline TiO2 with average crystallite sizes between 9 and 13 nm was extensively studied. On the basis of CO2-TPD (TPD = temperature-programmed desorption) and XPS (XPS = X-ray photoelectron spectroscopy) results, it was found that the amount of Ti3+ surface defects and photocatalytic activities of the prepared TiO2 depended strongly on the type of quenching media used in the following order: H2O2-RT > H2O2-373K > H2O-RT > H2O-373K > air-RT > air-373K, where RT = room temperature. However, the TiO2 sample that was slowly cooled after calcination (the nonquenched sample) also possessed a significant amount of Ti3+ surface defects and high photocatalytic activity to a degree similar to that quenched in H2O-RT. The effect of quenching was more pronounced on the smaller crystallite size TiO2 than on the larger ones due probably to its higher surface energy so that oxygen atoms were released more easily.

Preparation and characterization of CeO2/TiO2 nanoparticles by flame spray pyrolysis

“…It has found appeal to many potential applications including a semiconductor in dye-sensitized solar cell [1], water and air treatment materials [2,3], photocatalytic splitting of water for green-energy hydrogen fuel [4,5] and catalysts and catalyst supports [6]. Its performance in these applications depends on its physical and chemical properties which are related to synthetic conditions.…”

Effect of added ethanol in ethylene glycol–NaCl electrolyte on titanium electropolishing

“…In addition, the conduction band edge of Ti (Ti 4+ ) -O bonding in the E0-treated specimen is associated with disorderinduced, Ti 3+ -oxygen -vacancy complexes [27]. Therefore, the Ti 3+ point defects in the E0-treated sample are involved in the Ti (Ti 4+ ) -O bonding [28][29][30]. On the other hand, as shown in Fig.…”

Multi-layer three-dimensionally ordered Bismuth trioxide/Titanium dioxide nanocomposite: Synthesis and enhanced photocatalytic activity

“…However, there is one faintish diffraction peak of Bi 2 O 3 (JCPDS 73-1126) situated at 27.63°in the diffraction patterns of 3DOM Bi 2 O 3 /TiO 2 -X, which is attributed to the low-content of Bi 2 O 3 , and indicating the interaction between Bi 2 O 3 and TiO 2 [33,34]. The change trend of crystal grain size (Table 1) about 3DOM Bi 2 O 3 /TiO 2 -X is decreased firstly and then increased, of which 3DOM Bi 2 O 3 /TiO 2 -2 has relatively small crystallite size, which will exhibit higher photocatalytic activities [35][36][37]. Furthermore, the diffraction peak of 3DOM Bi 2 O 3 /TiO 2 -X at 25 …”