Tailoring Photocatalytic Activity of TiO₂ Nanosheets by ⁵⁷Fe

Abstract

TiO2 nanosheets were modified by two different procedures (volume and surface modification) with 0.5 wt % of 57Fe toward Ti. In the case of volume modification, the 57Fe (in the form of 57Fe­(NO3)3·nH2O solution) was added at the beginning of preparation of TiO2 nanosheets while the surface modified sample was prepared from the aqueous suspension of undoped TiO2 nanosheets annealed at 800 °C and solution of 57Fe­(NO3)3·nH2O via impregnation method. The volume modified sample was later annealed at 650, 800, and 950 °C; no further annealing was done on the surface modified sample. Both types of prepared materials were characterized by electron microscopy, X-ray powder diffraction, surface and porosity measurements, thermal analysis, FTIR and Raman spectroscopies, and Mössbauer spectroscopy. Photocatalytic activity was characterized from the results of 4-chlorophenol (4-CP) decomposition. The surface modified sample exhibited highly effective photocatalytic decomposition of a model pollutant under UV irradiation. On the other hand, the volume modification proved to suppress photocatalytic activity under UV. The visible light activity of 4-CP decomposition was negligible for both volume and surface modified samples. Mössbauer spectroscopy measurements confirmed the presence of iron atoms in the TiO2 structure. The surroundings of the iron atoms exhibit a structure close to that of mixed oxides (Fe1–x Ti2–x O5 and Fe2–x Ti x O3) in solid solution.

Surface Properties of 1DTiO2 Microrods Modified with Copper (Cu) and Nanocavities

“…The changes in lattice parameters as a function of temperature shown that in samples Cu/TiO2_500 and Cu/TiO2_650, the lattice parameter a decreases, and the parameter c increases with the increasing temperature. The increase of c axis lattice parameter with metal ions doping (Mo and Sc) in anatase NCs has already been reported in our recent works [22][23][24][25]. This further supports the substitutional incorporation of Cu 2+ ions into the anatase lattice.…”

“…Prepared materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) and porosity (BJH) measurement, thermal analysis (TG/DTA), Fourier transform infrared (FTIR), Raman spectroscopy, UV-Vis spectroscopy and PEC experiments (H2 generation by PEC water splitting). The whole set of instrumental characterization is described in our previous publication as you can see in [20][21][22][23][24][25].…”

Surface Properties of 1DTiO2 Microrods Modified with Copper (Cu) and Nanocavities

“…The changes in lattice parameters as a function of tempera-ture shown that in samples Cu/TiO 2 _500 and Cu/TiO 2 _650, the lattice parameter a de-creases, and the parameter c increases with the increasing temperature. The increase of c axis lattice parameter with metal ions doping (Mo and Sc) in anatase NCs has already been reported in our recent works [22][23][24][25]. This further supports the substitutional incor-poration of Cu 2+ ions into the anatase lattice.…”

“…Prepared materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area (BET) and porosity (BJH) measurement, thermal analysis (TG/DTA), Fourier transform infrared (FTIR), Raman spectroscopy, UV-Vis spectroscopy and PEC experiments (H 2 gen-eration by PEC water splitting). The whole set of instrumental characterization is de-scribed in our previous publication as you can see in [20][21][22][23][24][25].…”

Selective Thermal and Photocatalytic Decomposition of Aqueous Hydrazine to Produce H2 over Ag-Modified TiO2 Nanomaterial

“…On the other hand, metal-modified TiO 2 has been used as a photocatalyst under visible and solar light irradiations for H 2 generation via water splitting [ 17 ]. Therefore, various efforts have been devoted to tuning the band gap and electronic structure of TiO 2 by doping transition metals [ 18 , 19 ], nonmetals [ 20 ], noble metals [ 21 ], and through sensitization with dyes [ 22 ] for the improvement of its photocatalytic activity in the visible light region. It is well established that the photocatalytic activity of TiO 2 depends on the nature of metals and/or nonmetals and is extensively used for H 2 generation from splitting reactions under visible light irradiation (λ > 400 nm) for fuel cells [ 23 , 24 ].…”