FMR and photocatalytic
investigations of nFe-TiO
2
(n=1%, 5% and 10%) compounds
1, 2
2
1
2
2
N. Guskos , A. Guskos , S. Glenis , G. Zolnierkiewicz , J. Typek ,
2
3
3
4
3
P. Berczynski , D. Dolat , B. Grzmil , B. Ohtani , and A.W. Morawski
1
Department of Solid State Physics, Faculty of Physics, University of Athens,
Panepistimiopolis, 15 784 Zografou, Athens, Greece
2
Institute of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology,
Al. Piastow 48, 70-311 Szczecin, Poland
3
Department of Chemical and Environmental Engineering, West Pomeranian University of Technology,
Al. Piastów 17, 70-310 Szczecin, Poland
4
Catalysis Research Center, Hokkaido University, Sapporo 001-0021 Japan
Conclusions
Water suspension of a commercial amorphous titanium dioxide (TiO /A) from 2 sulfate technology supplied by “Chemical Factory Police S.A.” (Poland) was used as a starting material for the synthesis of (Fe,N)-co-modified rutile TiO photocatalysts. 2 Fe(NO ) ×9H O was used as a source of iron and ammonia (NH ) (Messer, 99.85%) was 3 3 2 3 used during the preparation process carried out in the furnace.
A defined amount of TiO water suspension, containing ca. 35wt.% of titanium 2 dioxide and ca. 8 wt.% of residual sulfuric acid as related to TiO content, was introduced 2 into a beaker containing aqueous solution of Fe(NO ) and stirred for 48h. The amount of 3 3 Fe introduced to the beaker was of 1 wt.%, 5 wt.% or 10 wt.% relatively toTiO content. 2 After water evaporation, the samples were dried at 80 ºC for 24 h in an oven. Subsequently, the material was calcined at 800 ºC in NH flow (co-modified samples denoted as XFe,N-3 TiO /800).2
Samples preparation
0 2000 4000 6000 8000 10000 -80000 -60000 -40000 -20000 0 20000 40000 d c "/ d H [A rb . u n it s ] Magnetic field [G] 4 K 10.2 K 30 K 50 K 80 K 110 K 160 K 220 K 290 K 1% Fe 0 2000 4000 6000 8000 10000 -90000 -80000 -70000 -60000 -50000 -40000 -30000 -20000 -10000 0 10000 20000 30000 d c "/ d H [A rb . u n it s ] Magnetic field [G] 4 K 10 K 30.4 K 50 K 80 K 110 K 160 K 220 K 290 K 5% Fe 0 2000 4000 6000 8000 10000 -100000 -80000 -60000 -40000 -20000 0 20000 40000 60000 d c "/ d H [A rb . u n it s ] Magnetic field [G] 4 K 10 K 30.5 K 50 K 80 K 110 K 160 K 220 K 290 K 10% Fe 0 2000 4000 6000 8000 10000 -20000 -15000 -10000 -5000 0 5000 10000 20 K d c "/ d H [a rb . u n it s ] Magnetic field [G] 1% Fe 5% Fe 10% Fe 0 2000 4000 6000 8000 10000 -25000 -20000 -15000 -10000 -5000 0 5000 10000 15000 150 K d c "/ d H [a rb . u n it s ] Magnetic field [G] 1% Fe 5% Fe 10% Fe 0 2000 4000 6000 8000 10000 -30000 -25000 -20000 -15000 -10000 -5000 0 5000 10000 15000 20000 d c "/ d H [a rb . u n it s ] Magnetic field [G] 1% Fe 5% Fe 10% Fe 290 K 0 30 60 90 120 150 180 210 240 270 300 0 4000 8000 12000 16000 L in e w id th 2 [G ] Temperature [K] 30 60 90 120 150 180 210 240 270 0 5000 10000 15000 20000 25000 L in e w id th 1 [G ] 30 60 90 120 150 180 210 240 270 4000 8000 12000 16000 20000 R e s o n a n c e fi e ld [G ] 30 60 90 120 150 180 210 240 270 0.00E+000 5.00E+012 1.00E+013 1.50E+013 2.00E+013 2.50E+013 10% Fe Component 1 Component 2 Component 3 A m p li tu d e [a rb . u n it s ] 0 30 60 90 120 150 180 210 240 270 300 0 500 1000 1500 2000 2500 L in e w id th 2 [G ] Temperature [K] 30 60 90 120 150 180 210 240 270 0 5000 10000 15000 20000 25000 30000 L in e w id th 1 [G ] 30 60 90 120 150 180 210 240 270 4000 6000 8000 10000 12000 R e s o n a n c e fi e ld [G ] 30 60 90 120 150 180 210 240 270 6.00E+011 8.00E+011 1.00E+012 1.20E+012 1.40E+012 Component 1 Component 2 A m p li tu d e [a rb . u n it s ] 5% Fe 0 30 60 90 120 150 180 210 240 270 300 0 1000 2000 3000 4000 5000 L in e w id th 2 [G ] Temperature [K] 30 60 90 120 150 180 210 240 270 0 2000 4000 6000 8000 L in e w id th 1 [G ] 30 60 90 120 150 180 210 240 270 2000 4000 6000 8000 10000 12000 14000 R e s o n a n c e fi e ld [G ] 30 60 90 120 150 180 210 240 270 5.00E+011 1.00E+012 1.50E+012 2.00E+012 2.50E+012 3.00E+012 1% Fe Component 1 Component 2 Component 3 A m p li tu d e [a rb . u n it s ]Magnetic resonance spectra were registered on BRUKER E500 X-band (9.4 GHz) spectrometer equipped with Oxford helium flow cryostat enabling measurements in 4-300 K temperature range.
Apparatus
( )
(
)
( )
[
]
( )
(
)
[
]
[
( )
(
)
2]
0 2 0 2 0 2 0 2 0 2 0 2 2 0 2 0 0 2 2 2 0 2 02
)
(
B B B B B B B B BH
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
I
d
d
d
d
+
D
+
+
+
D
+
-D
+
+
+
D
D
+
µ
where H is the true resonance field, Ä is the true linewidth connected with relaxation of the Landau-Lifshitz 0 H type, and ä a true linewidth connected with relaxation of the Bloch-Bloembergen type.H
To determine the magnetic properties of the investigated
samples and to corelate them with photocatalityc activity.
Aim of the work
Some of the registered FMR spectra at different
temperatures of 1 Fe,N-TiO /800, 5 Fe,N-TiO /800, 10 2 2
Fe,N-TiO /800 samples. 2
Experimental (symbol) and fitted (solid line) spectra of unit mas samples, at three selected temperatures.
Spectra of samples 1 Fe,N-TiO /800 and 10 Fe,N-TiO /800 2 2
were fitted with three Callen-shape components, while sample
5 Fe,N-TiO /800 was fitted with two Callen-shape component.2
Temperature dependence of calculated parameters obtained from fitting the FMR spectra with Calen-shape components. Temperature dependence of the integrated intensity. The inset shows the integrated intensities of all three samples at RT. 0 50 100 150 200 250 300 0 2 4 6 1% Fe 5% Fe 10% Fe 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 In te g ra te d in te n s it y [a rb . u n it s ] Temperature [K] 1% Fe 5% Fe 10% Fe 290 K 1% Fe 5% Fe 10% Fe 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 C O 2 e v o lu ti o n ra te [ m m o l/ m in ]
CO photocatalytic evolution during acetic acid 2
decomposition under mercury lamp in the presence of
Fe,N-co-modified TiO2
The Callen-lineshape
· The FMR spectra have been satisfactorily fitted with the Callen-type lineshape components: two componenents in case of n=5% sample and three components for n=1% and 10%
samples.
· The anisotropy field is the biggest in n=10% sample (B ~14 kG), smaller in n=1% sample a
(B ~10 kG) and the smallest in n=5% (B ~5 kG).a a
· The integrated intensity follows the same tendency as the anisotropy field: the smallest is for n=5% sample, the largest for n=10% sample.
· The photocatalytic activity follows the reverse tendency of the anisotropy field and the integrated intensity: sample n=5% showed the biggest activity, sample n=10% the smallest photocatalytic activity.
