an Ag/AgCl (saturated KCl solution) reference electrode in an oxygen-free 0.5 M NaClO4 (A) and. Na2SO4 (B) solution. 0. 600 1200 1800 2400 3000 3600. 0. 2.
Electronic Supplementary Information (SI) Exceptional performance of photoelectrochemical water oxidation of single-crystal rutile TiO2 nanorods dependent on the hole trapping of modified chloride Xuliang Zhang, Haiqin Cui, Muhammad Humayun, Yang Qu, Xiaojun Sun*, and Liqiang Jing*
SI-Figures: Figure S1 XRD patterns (A) and UV-vis spectra (B) of different TiO2 samples prepared by varying the concentration of HCl solution used from 0 to 3.0 M. TX indicates the resulting TiO2 unless stated elsewhere, in which T means TiO2 and X is the concentration of used HCl solution. EDX spectroscopy. 100
A
UV-vis DRS ( % )
Intensity (a.u.)
T3.0 T2.5 T2.0 T1.5 T1.0 T0
20
30
40
50
60
2 theta (degree)
70
80
B
80 60
T0 T1.0 T1.5 T2.0 T2.5 T3.0
40 20 0 300
350
400
450
500
550
600
Wavelength (nm)
1
Ti2p
O1s
T3.0
T3.0
T2.5 T2.0 T1.5 T1.0
Intensity (a. u.)
Intensity (a.u.)
Figure S2 XPS spectra of Ti2p (A), O1s (B), and Cl2p (C) of different TiO2 samples.
T2.5 T2.0 T1.5 T1.0
T0
452
456
460
464
T0
468
526
528
530
532
534
536
Binding energy (eV)
Binding energy (eV)
Cl2p
Intensity (a. u.)
T3.0 T2.5 T2.0 T1.5 T1.0 T0
196
198
200
202
204
206
Binding energy (eV)
2
Figure S3 XRD patterns (A) and SEM images (B) of different TiO2 films. A
Intensity (a.u.)
T3.0
T2.5
T1.5 T0
20
30
40
50
60
70
80
2 theta (degree)
Figure S4 I-t curves of T0 and T2.5 samples under illumination. Potentials are measured against an Ag/AgCl (saturated KCl solution) reference electrode in an oxygen-free 0.5 M NaClO4 (A) and Na2SO4 (B) solution. 8
A
in NaClO4
6
T2.5
4 T0
2 0
0
600
1200 1800 2400 3000 3600
Time (s)
Current density (mA / cm2)
Current density (mA/cm2)
8
B
in Na2SO4 T2.5
6 4
T0
2 0
0
600
1200 1800 2400 3000 3600
Time (s)
3
Figure S5 XRD patterns (A), SPS responses in different atmospheres (B), and I-V curves (C) of rutile TiO2 (T0-800) prepared by calcining T0 at 800 ºC. To compare, the T0 is also included here.
T0-800
Photovoltage (a.u.)
Intensity (a.u.)
A
100% O2 20% O2 N2
T0-800
B
T0
20
30
40
50
60
70
80
2 theta (degree)
Current density (mA / cm2)
3.0
300
350
400
450
500
Wavelength (nm)
C
2.5 2.0
T0 T0-800
1.5 1.0 0.5 0.0 -0.4
0.0
0.4
0.8
1.2
1.6
Potential (V) vs Ag / AgCl
4
Figure S6 XRD patterns (A), XPS spectra of Cl2p (B), SPS responses in different atmospheres (C), and I-V curves (D) of TiO2-Cl-free nanorod (T2.5-treated) treated by the twice hydrothermal process. To compare, the T2.5 is also included here. Potentials are measured against an Ag/AgCl (saturated KCl solution) reference electrode in an oxygen-free 0.5 M NaClO4 solution. The SPS responses in different atmospheres of T2.5 is as taken as the inset. Cl2p
B
T2.5-Cl-free
T2.5
Intensity (a.u.)
Intensity (a.u.)
A
T2.5-Cl free
T2.5
10
20
30
40
50
60
70
196
80
198
Photovoltage (a.u.)
Photovoltage (a.u.)
T2.5 N2 air O2
300
350
400
450
500
Wavelength / nm
O2 Air N2
300
350
400
450
T2.5-Cl-free 500
Wavelength (nm)
550
600
Current density (mA/cm2)
8
C
200
202
204
206
1.2
1.6
Binding energy (eV)
2 theta (degree)
7
D
6
T2.5 T2.5-Cl-free
5 4 3 2 1 0 -0.4
0.0
0.4
0.8
Potential (V) vs Ag / AgCl
5
Figure S7 XRD patterns (A), SPS responses in different atmospheres (B), and I-V curves (C) of H3BO3-modified T2.5 (B-T2.5). Potentials are measured against an Ag/AgCl (saturated KCl solution) reference electrode in an oxygen-free 0.5 M NaClO4 solution. To compare, the T2.5 is also included here. A
B-T2.5
B-T2.5
Photovoltage (a.u.)
Intensity / a.u.
B O2 air N2
T2.5
20
30
40
50
60
70
80
2 theta / degree
Current density (mA / cm2)
8
300
350
400
450
500
Wavelength / nm
C
6
T2.5 H3BO3-modified T2.5
4 2 0 -0.4
0.0
0.4
0.8
1.2
1.6
Potential (V) vs Ag / AgCl
6
Figure S8 XRD patterns (A), DRS spectra (B), Cl2p XPS spectra (C), SPS responses of T0-0.5NaCl in different atmosphere (D), I-V curves (E) and produced O2 amount (F) of different chloride-functionalized anatase TiO2 (T0-XNaCl), in which X indicates the mass of the NaCl added during the modification process. Potentials are measured against an Ag/AgCl (saturated KCl solution) reference electrode in an oxygen-free 0.5 M NaClO4 solution. A
100 B
T0-0.7NaCl T0-0.5NaCl T0-0.3NaCl
UV-vis DRS ( % )
Intensity / a.u.
T0-1.0NaCl
80 60 40 20
T0
20
30
40
50
60
T0 T0-0.3NaCl T0-0.5NaCl T0-0.7NaCl T0-1.0NaCl
0 300
70
350
2 theta (degree)
Cl2p
C
T0-0.3NaCl
T0
200
202
204
300
206
350
O2detector reading (a.u.)
Current density (mA / cm2)
E 3
2
0 -0.4
T0-0.5NaCl T0-0.3NaCl T0-0.7NaCl T0-1.0NaCl T0
0.0
0.4
0.8
550
600
400
450
500
550
600
Wavelength (nm)
Binding energy (eV)
1
500
N2 air O2
Photovoltage (a.u.)
Intensity (a.u.)
T0-0.5NaCl
198
450
D
T0-1.0NaCl T0-0.7NaCl
196
400
Wavelength / nm
1.2
Potential (V) vs Ag / AgCl
1.6
F
80
T0 T0-0.3NaCl T0-0.5NaCl T0-0.7NaCl T0-1.0NaCl
70 60 50 0
200
400
600
800
1000 1200
Time (s)
7
Figure S9 I-V curves (A) and O2 evolution (B) of T2.5-Cl-free. Potentials are measured against an Ag/AgCl (saturated KCl solution) reference electrode in an oxygen-free 0.5 M NaClO4 solution and an oxygen-free 0.5 M NaClO4 / 0.01 M NaCl solution.
14 12 10 8 6 4 2 0
0.0
64
A
with NaCl without NaCl
O2 detector reading (a.u.)
Current density (mA / cm2)
16
0.5
1.0
1.5
Potential (V) vs Ag / AgCl
B
without NaCl with NaCl
60 56 52 48 0
100
200
300
400
500
600
Time (s)
Figure S10 I-V curves under illumination (solid lines) and in the dark (dash lines). Potentials are measured against an Ag / AgCl (saturated KCl) reference electrode in a nitrogen purged 0.5M NaClO4 (aq) solution. (a) T2.5, (b) T2.5-Cl-free, (c) 0.0045M Methanol-T2.5-Cl-free, (d) 0.009M Methanol-T2.5-Cl-free.
Current density (mA/cm2)
14 12 10
d a c b
8 6 4 2 0 -0.4
0.0
0.4
0.8
1.2
1.6
Potential (V) vs Ag / AgCl
8
Figure S11 I-V curves under illumination (solid lines) and in the dark (dash lines) (A) Potentials are measured against an Ag / AgCl (saturated KCl) reference electrode in a nitrogen purged 0.5M NaClO4 (aq) solution,(a) T2.5, (b) T2.5-Cl-free, (c) 2×10-3 Co-P-T2.5-Cl-free, (d) 5×10-3 Co-P-T2.5-Cl-free, (e) 8×10-3 Co-P-T2.5-Cl-free. IPCE value of T0 and T2.5 under 365nm wavelength illumination (B). A
8 6
7 a d c e b
6.72
5
4 2 e d c
0 -0.4
B
6
IPCE (%)
Current density (mA / cm2)
10
0.0
0.4
0.8
1.2
Potential vs Ag / AgCl (V)
b
a
1.6
4 3
2.66
2 1 0
T0
T2.5
Samples
9
