Improvement of the photocatalytic properties of TiO2 by (Fe+Mo) co-doping—A possible way to retard the recombination process

Abstract

Low visible light absorption and high charge carrier recombination rate are two main disadvantages of TiO2 as a photocatalyst which severely limit its practical applications. To overcome the problems, Fe mono-doped and (Fe+Mo) co-doped TiO2 were synthesized and studied. It was found that (Fe+Mo) co-doping can further increase the visible absorption and improve the photocatalytic property of TiO2 compared with Fe mono-doping; Fe mono-doping improves the photocatalytic property of TiO2 only at very low doping level (Fe concentration less than 1.0%), while by co-doping a small amount of Mo with Fe, the effective doping concentration of Fe can be pushed to a higher level and the photocatalytic property of TiO2 can be further improved. Photoluminescence spectra indicated that Mo dopant may play a role in retarding the recombination process when co-doped into TiO2 with Fe. The mechanism behind was discussed. It was suggested that doping a small amount of Mo into Fe-TiO2 might be an efficient way to further improve the photocatalytic property of Fe-TiO2 without losing its photocatalytic specificity.

Theoretical study on cation codoped SrTiO3 photocatalysts for water splitting

“…Since most of the metal-oxide photocatalysts, including perovskites, have too large optical band gaps for visible light, many efforts have been directed to a reduction by chemical doping. For example, cation-cation codoping of TiO 2 has been investigated experimentally for (Ni/Zn/Mo, Fe) [1][2][3][4], (Co/Nb/Ta, Ni) [5][6][7], (Y, V) [8], (Sb, Cr) [9], (Rh, Sr) [10] and theoretically for (Ni, Fe) [11], (Rh, Nb) [12], (Mo/W, Mg/Ca) [13], (La, Mn) [14]. Other studies have addressed (La, Ag) codoping of CaTiO 3 [15], (Sn, Ga) codoping of BiFeO 3 [16], and (W, Fe/Mo) codoping of BiVO 4 [17,18].…”

Photoelectric conversion performances of Mn doped TiO2 under >420nm visible light irradiation

“…6b). It is concluded that high level doping may cause too many lattice defects, which can act as recombination centers for electron and holes so that they degrade the conversion performance [39]. The competitive growth of rutile when Mn content is higher than 6% may also influence the photo sensitivity of TiO 2 [40].…”

Reduced graphene oxide-supported Ag-loaded Fe-doped TiO2 for the degradation mechanism of methylene blue and its electrochemical properties

“…Since Fe 3+ in the 3d orbital is half lled, as Fe 3+ is doped into TiO 2 , the empty E g state is near the bottom of the conduction band, while the occupied t 2g state of Fe is located at the top of the valence band. 46 There are multiple electronic 2 T 1g ) or to the charge transfer transition between interacting iron ions via the conduction band (Fe 3+ + Fe 3+ / Fe 4+ + Fe 2+ ). 11,47,48 For rGO/Ag/ Fe-doped TiO 2 , there is a broad range absorption in the visible region, mainly due to the local surface plasmonic resonance (LSPR) effect of Ag nanoparticles.…”

“…53 As Fe was doped into TiO 2 , a new characteristic peak located at 575 cm À1 was attributed to the stretching vibration of the Fe-O bond. 46 Aer rGO connected with Fedoped TiO 2 -based specimens, several functional groups could be seen, such as the peak located at 1571 cm À1 corresponding to C]C aromatic bonding, and the lowering of the absorption peak at around 1705 cm À1 assigned to the C]O stretching accredited to rGO. Typically, Ti-O-Ti and Ti-O-C bonds can be seen at low frequency bands around 450 to 900 cm À1 , and their shiing towards a higher wavenumber, compared with Fedoped TiO 2 , indicates the chemical interaction of Fe-doped TiO 2 with rGO.…”