Solar photoactivity of nano-N-TiO2 from tertiary amine: role of defects and paramagnetic species

Abstract

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Unraveling the Cooperative Mechanism of Visible-Light Absorption in Bulk N,Nb Codoped TiO2 Powders of Nanomaterials

“…Indeed, previous studies have shown that the actual nitrogen content in TiO2 lattice is generally much lower than the nominal amount, since an appreciable loss of N containing species occurs during calcination. 11,14 Nitrogen bulk quantification is quite a challenging task, since conventionally used techniques, such as X-ray photoelectron spectroscopy (XPS), provide information about the surface and near-subsurface composition of the oxide, which is greatly influenced by the presence of atmospheric contaminants (C, N and O). 8 Previous studies on Nb-doped TiO2 have also underlined other relevant discrepancies between bulk and surface compositions in such systems, such as a higher Nb content at the surface due to the occurrence of surface segregation phenomena 58 .…”

“…[11][12][13] However, such shallow mid-gap levels can also act as recombination centers for photogenerated charge carriers, lowering the quantum efficiency of the photoinduced process. 11,14 Further, the limited structural stability of N-doped TiO2 represents another unresolved issue. 7,15 As for cationic dopants, the use of several metals of the first transition series has been proposed.…”

Visible light active N-doped TiO2 prepared from different precursors: Origin of the visible light absorption and photoactivity

“…Spadavecchia et al synthesized nano-N-TiO 2 via a controlled sol-gel reaction at pH 9 followed by calcinations at 400 • C and ascribed their N 1s peak centered at ca. 399 eV to oxidized nitrogen (i.e., N-O-Ti-O species), possibly in interstitial location [35]. Li et al prepared N-doped TiO 2 by pretreating TiO 2 precursor in NH 3 /ethanol fluid under supercritical conditions and observed two kinds of N species, O-Ti-N and surface adsorbed NH 3 molecules with a binding energy of 399.5 eV and 395.3 eV, respectively [36].…”

Atypical BiOCl/Bi2S3 hetero-structures exhibiting remarkable photo-catalyst response

“…Two major approaches have been employed to extend the light absorption of semi-conductor photocatalysts to visible spectral region. The first one is the modification of TiO 2 through metals or non-metal doping and semiconductor coupling [28,29]. The second strategy is to exploit novel non-TiO 2 -based semiconductor photocatalysts displaying strong visible light response.…”