Electronic Supplementary Material (ESI) for Dalton Transactions.
This journal is © The Royal Society of Chemistry 2014
Supporting Information for:
In situ synthesis of uniform Fe2O3/BiOCl p/n heterojunction and
the improved photodegradation properties for mixture dyes
Na Li, Xia Hua, Kai Wang, Yujian Jin, Jingjing Xu, Mindong Chen and Fei Teng 
Jiangsu Engineering and Technology Research Center of Environmental Cleaning
Materials (ECM), Jiangsu Key Laboratory of Atmospheric Environment Monitoring
and Pollution Control (AEMPC), Jiangsu Joint Laboratory of Atmospheric Pollution
Control (APC), Collaborative Innovation Center of Atmospheric Environment and
Equipment Technology (AEET), School of Environmental Science and Engineering,
Nanjing University of Information Science & Technology，219 Ningliu Road,
Nanjing 210044, China. Email: [email protected] (F. Teng); Phone/Fax: +86-2558731090
Corresponding
author. Email: [email protected] (F. Teng); Phone/Fax: 0086-25-58731090
1
Preparation of BiOCl sample. Typically, 1.5 mmol of Bi(NO3)3·5H2O was dissolved
in 30 mL of EG stirring at room temperature. After the Bi(NO3)3·5H2O was
completely dissolved, 10 mmol of the NaCl was added to the above solution. A
transparent solution was obtained and then transferred into a Teflon-lined stainless
steel autoclave to fill 85% of the total volume. The autoclave was sealed and
maintained at 170 °C for 6 h. After the reaction was completed, the autoclave was
then allowed to cool naturally to room temperature, and a white powder was obtained.
Finally, the powder was centrifuged and washed with distilled water for several times
and then dried at 60 °C for 5 h.
Table S1 The nominal and real Fe/Bi ratios of the Fe2O3/BiOCl samples (x/y, the
molar ratio of Fe2O3 to BiOCl)
[a] xFe/yBi
[b]Fe
[b]Bi
(Nominal molar ratio)
(wt%)
(wt%)
[c]
xFe/yBi
(Real molar
ratios)
5/100
1.34
87.94
2.8:100
10/100
1.83
88.59
3.9:100
20/100
2.95
88.12
6.2:100
30/100
6.41
81.27
14.7:100
40/100
8.28
78.39
19.7:100
Notes: [a], Nominal molar ratio of Fe2O3 to BiOCl; [b], Real mass ratio of Fe to Bi
measured using inductive coupled plasma emission spectrometer (ICP); [c], Real molar
ratio of Fe2O3 to BiOCl calculated on base of the ICP results
From the Table S1, the real molar ratios of xFe/yBi samples are far lower than the
nominal molar ratios, which is due to the incomplete hydrolysis of FeCl3.
2
1.0
C/C0
0.8
0.6
0.4
0.2
0.0
20Fe/100Bi
30Fe/100Bi
40Fe/100Bi
0
20
40
60
80
100 120 140 160 180
time/min
Fig. S1. Photodegradation curves of rhodamine B (RhB) over the typical xFe/yBi
samples under visible light irradiation (≥420 nm)
It is observed from Fig. S1 that the xFe/yBi samples almost have no photocatalytic
activity under visible light irradiation (≥420 nm). It has been reported that due to a
short diffusion length of the photogenerated holes in the Fe2O3, the photogenerated
electron–hole pairs can not be easily separated [1-3]. Therefore, the photocatalytic
activities of the xFe/yBi samples were evaluated under ultraviolet light (λ ≤ 420 nm).
[1] S. Li, G.W. Qin, X.Y. Meng, Y.P. Ren, L. Zuo, Journal of Materials Science 48
(2013) 5744–5749.
[2] S.W. Zhang, W.Q. Xu, M.Y. Zeng, J.X. Li, J.Z. Xu, X.K. Wang, Dalton
Transactions 42 (2013) 13417–13424.
[3] A. Kay, I. Cesar, M. Grätzel, Journal of the American Chemical Society 128 (2006)
15714–15721
3
(a)
(b)
100 nm
(c)
Fig. S2.
(d)
Transmission electron microscope (TEM) images of the xFe/yBi sample:
(a), x/y = 10/100; (b), x/y = 20/100; (c), x/y = 30/100; (d), x/y = 40/100
As shown in Fig. S2, the Fe2O3 nanoparticles are deposited on the surface of BiOCl
nanosheets at lower Fe/Bi ratios. With further increasing the ratio of Fe2O3 to BiOCl,
the mean size of Fe2O3 nanoparticles increases, namely, the mean sizes of Fe2O3
nanoparticles at x/y = 10/100, 20/100, 30/100 and 40/100 Bi sample are about 30, 40,
60 and 100 nm, respectively. Besides, with increasing x/y ratio, more Fe2O3
nanoparticles have agglomerated and even separated from the surface of BiOCl (Fig.
S2d).
4
C/C0
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0Fe/100Bi
5Fe/100Bi
10Fe/100Bi
20Fe/100Bi
30Fe/100Bi
40Fe/100Bi
100Fe/0Bi
0
10
20
30
40
50
60
Time/min
Fig. S3. Methylene blue (MB) photodegradation over xFe/yBi samples under
ultraviolet light irradiation ( ≤ 420 nm)
Methylene blue (MB) was degraded by the as-prepared xFe/yBi samples under
ultraviolet light irradiation, as shown in Fig. S3. It is clear that the xFe/yBi samples
show greatly improved photocatalytic activity, compared with the pure BiOCl and
Fe2O3, and the optimum molar ratio of the Fe2O3 to BiOCl is 10/100 for the
degradation of MB.
5
Table S2 Degradation efficiencies of the RhB-MO mixture solution over the xFe/yBi
samples after 20 min UV irradiation (λ ≤ 420 nm)
xFe/yBi samples
Degradation percent of RhB
Degradation percent of MO in
in mixture solution (%)
mixture solution (%)
0Fe/100Bi
15%
31%
5Fe/100Bi
59%
86%
10Fe/100Bi
50%
84%
20Fe/100Bi
22%
40%
30Fe/100Bi
22%
52%
40Fe/100Bi
14%
47%
100Fe/0Bi
3%
6%
200 mL of 10 mgL-1 RhB + 10 mg L-1 MO
6
0.20
RhB
MO
1- C/C0
0.15
0.10
0.05
0.00
0
10
20
30
40
50
Adsorption time (min)
60
Fig. S4. The adsorption amounts of the RhB and MO in the RhB-MO mixture solution
(200 mL, 10 mg/L RhB + 10 mg/L MO) at different times over the 5Fe/100Bi sample
under dark condition
7
SO3Na
(a)
(b)
N
N
COOH
N(CH3)2
(C2H5 )2N
O
Fig. S5. Molecular structures of the MO (a) and RhB (b)
8
N(C2H5)2
0.25
0Fe/100Bi
5Fe/100Bi
30Fe/100Bi
100Fe/0Bi
Absorbance(a.u.)
0.20
0.15
0.10
0.05
0.00
200
300
400
500
600
Wavelength(nm)
700
800
Fig. S6. UV–vis diffuse reflectance spectra (UV-DRS) of the typical xFe/yBi samples
Fig. S6 shows the UV–DRS spectra of the typical xFe/yBi samples. When the
Fe2O3 were loaded on the surface of the BiOCl sample, the absorption ability of light
was enhanced in the wavelength range of 340 – 540 nm. It was also found that the
absorption of xFe/yBi samples in the ultraviolet light range apparently increased and
a red shift appeared upon the addition of the Fe2O3. The absorption ability of light of
the 30Fe/100Bi was greater than that of the 5Fe/100Bi, but the degradation rates of
dyes were lower than that of the 5Fe/100Bi. The possible reason may be that too
much amount of Fe2O3 would agglomerate or grow into large particles, resulting in
the decease of active sites.
9