Dynamic ESR Study of Oxygen Chemisorption on TiO2-Based Catalysts

The enhancement of TiO2 photocatalytic activity by hydrogen thermal treatment

“…This founding was in agreement with that by Heller et al (1987). On the other hand, it has been indicated that the thermal H 2 treatment of TiO 2 at 550°C may produce OV and Ti 3þ species (Harris and Schumacher, 1980), which exist even on the TiO 2 surface as it is prepared originally (Qin et al, 1993). In this study, the H 2 consumption during the treatment was monitored by the TPR measurement in order to further investigate the H 2 treatment process.…”

“…In the meantime, the photoactivity of the TiO 2 pigment can be enhanced by this reduction reaction in a H 2 atmosphere at a thermal condition (Heller et al, 1987). The H 2 treatment was a usual method to improve the surface and photoelectrochemical properties of TiO 2 (Chen et al, 1983;Howe and Gr€ a atzel, 1987;Qin et al, 1993;Rekoske and Barteau, 1997). More recently, some researchers have investigated the reduction mechanism in the temperature range of 300-500°C (Khader et al, 1993) and the surface stoichiometry (Haerudin et al, 1998) of the TiO 2 with H 2 treatment by means of Chemosphere 50 (2003) [39][40][41][42][43][44][45][46] www.elsevier.com/locate/chemosphere electrical conductivity (Khader et al, 1993) or Fourier transform infrared (FTIR) spectroscopy (Haerudin et al, 1998).…”

Photochemistry of Methanol and Methoxy Groups Adsorbed on Powdered TiO2

“…TiO 2 is a semiconductor with ∼3.1 eV (400 nm) band gap. On evacuation at ∼500 °C, TiO 2 powders retain partial OH (a) groups on the surface 3,4 and lose part of O atoms to form F-centers 19 and Ti 3+ 19,20 as concluded by electron spin resonance studies. Upon irradiation with UV light at 3.4 eV, Ti 3+ defects are enhanced on a nearly defect-free TiO 2 (110) single-crystal surface as evidenced by X-ray photoelectron spectroscopy.…”

Highly enhanced visible-light photocatalytic NO x purification and conversion pathway on self-structurally modified g-C 3 N 4 nanosheets

“…Recently, it was found that the photocatalytic activity of TiO 2 can be significantly enhanced by self-structural modification without recruiting any foreign elements, compounds, or other species besides the normal valence states of Ti 4+ and O 2À in TiO 2 [17]. The TiO 2 nanomaterials produced through self-structural modification in pure [18][19][20], mixed [21][22][23][24][25][26], amorphous/disordered [27,28], and hydrogenated phases [29][30][31][32][33][34]. Most of the selfstructural modification strategies focus on oxide semiconductors and are related to oxygen vacancies.…”