S1
SUPPORTING INFORMATION
Porous NiTiO3/TiO2 nanostructures for photocatatalytic
hydrogen evolution
Congcong Xing,ab
Yongpeng Liu,c Yu Zhang,
a Junfeng Liu,
a Ting Zhang,
d Pengyi Tang,
d Jordi Arbiol,
de Lluís
Soler,b Kevin Sivula,
c Néstor Guijarro,
c Xiang Wang,
a Junshan Li,
a Ruifeng Du,
a Yong Zuo,
a Andreu
Cabot,*ae
Jordi Llorca *b
a. Catalonia Institute for Energy Research (IREC), Sant Adrià de Besòs, 08930 Barcelona, Spain
b. Institute of Energy Technologies, Department of Chemical Engineering and Barcelona Research Center in Multiscale Science and
Engineering, Universitat Politècnica de Catalunya, EEBE, 08019 Barcelona, Spain
c. Laboratory for Molecular Engineering of Optoelectronic Nanomaterials (LIMNO), École Polytechnique Fédérale de Lausanne
(EPFL), Station 6, CH-1015 Lausanne, Switzerland
d. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona,
Catalonia, Spain
e. ICREA, Pg. Lluis Companys 23, 08010 Barcelona, Spain
* E-mails: A. Cabot: [email protected]
J. Llorca: [email protected]
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2019
S2
Content
1. Photoreactor ............................................................................................................................................. 3
2. Additional SEM characterization of the precursor materials ............................................................. 4
3. Additional TEM characterization .......................................................................................................... 5
4. Elemental composition ............................................................................................................................ 6
5. Scheme of the preparation procedure.................................................................................................... 7
6. EELS elemental maps and HRTEM of TiO2 ........................................................................................ 8
7. XRD Rietveld refinement ........................................................................................................................ 9
8. HRTEM characterization of NiTiO3/TiO2 (1%) ................................................................................. 10
9. XPS analyses .......................................................................................................................................... 11
10. TiO2:Ni annealed in argon ................................................................................................................ 12
11. Nitrogen adsorption-desorption isotherms...................................................................................... 13
12. NiTiO3 reference material ................................................................................................................. 14
13. Literature comparison ...................................................................................................................... 15
14. Photocatalytic H2 production rates .................................................................................................. 16
15. UV-vis analysis ................................................................................................................................... 17
References ...................................................................................................................................................... 18
S3
1. Photoreactor
Figure S1. a) Photograph of the system used to test the photocatalytic hydrogen generation: 1
displays the Dreschel bottle containing the ethanol-water solution (1:9 molar). 2 displays the actual
photoreactor. b) Scheme of the photoreactor.
1 2a b
Gas flow from reactant
Uvlight
Gas flow to GC
paper +material
o-ring
paper material
Uv light
o-ring
Class Tube
Class Tube
c
S4
2. Additional SEM characterization of the precursor materials
Figure S2. SEM images of TiO2:Ni (5%) produced in the following conditions: a) without HDA, b)
without H2O, c) in HDA-H2O-KCl.
200 nm 1 µm 1 µm
a b c
S5
3. Additional TEM characterization
Figure S3. TEM images of (a) TiO2, (b) TiO2:Ni (1%), (c) TiO2:Ni (2%).
200 nm 200 nm 200 nm
ca b c
S6
4. Elemental composition
Table S1. Ti and Ni atomic concentrations of TiO2, TiO2:Ni (1%, 2%, 5%) and NiTiO3/TiO2 (1%,
2%, 5%). XRD data refers to the TiO2 and NiTiO3 crystallographic phases detected and it does not
take into account any peak shift denoting the presence of Ni within the TiO2 structure.
catalysts EDX XRD XPS
Ti (atom%) Ni (atom%)Ti (atom%) Ni (atom%)Ti (atom%) Ni (atom%)
TiO2 100
TiO2:Ni (1%) 96.4 3.6 94.3 5.7
TiO2:Ni (2%) 93.6 6.4
TiO2:Ni (5%) 83.2 16.8
NiTiO3/TiO2 (1%) 96.4 3.6 4.4 95.6 94.2 5.8
NiTiO3/TiO2 (2%) 94.3 5.7 6.5 93.5
NiTiO3/TiO2 (5%) 86 14 13.3 86.7
NiTiO3 61.9 39.1
S7
5. Scheme of the preparation procedure
Figure S4. Scheme of the TiO2:Ni precursor preparation procedure: (a) TiO2:Ni, (b) NiOx/TiO2, (c)
NiTiO3/TiO2.
170oC
(a)
(b)
(c)
S8
6. EELS elemental maps and HRTEM of TiO2
Figure S5. Undoped TiO2 annealed at 650 °C in air: (a) STEM micrograph and EELS chemical
composition maps obtained from the yellow squared area of the STEM micrograph. Individual Ti
L2,3-edges at 456 eV (red) and O K-edge at 532 eV (green) as well as its composite. (b) HRTEM
micrograph, detail of the yellow squared region and its corresponding power spectrum.
(10-1)
(004) (103)
[010] Anatase TiO2
a b
[010] TiO2 I41MADS
S9
7. XRD Rietveld refinement
Figure S6 Refined fitting of the NiTiO3/TiO2(5%) x-ray diffraction data. Blue symbols:
experimental data; continuous red line: modified background; continuous green line: calculated
modelled structure; continuous light blue line beneath pattern: difference between observed and
calculated parameters. Blue tickmarks correspond to reflections of NiTiO3 (R-3) unit cell, lower red
ones to TiO2 (I41/amd) unit cell. GOF = 1.21. Rw = 6.99%.
[010] TiO2 I41MADS
S10
8. HRTEM characterization of NiTiO3/TiO2 (1%)
Figure S7 HRTEM micrographs of NiTiO3/TiO2 (1%), detail of the yellow squared region and its
corresponding power spectrum.
(002)
(101)
(10-1)
[010] TiO2 I41MADS
[010] TiO2 I41MADS
S11
9. XPS analyses
Figure S8. Ni 2p3/2 region (a), O 1s region (b) and Ti 2p region (c) of the XPS spectra of (1)
TiO2:Ni (1%) (2) NiOx/TiO2 (1%) and (3) NiTiO3/TiO2 (1%) samples.
Figure S9. Survey XPS spectra of TiO2:Ni (1%), NiOx/TiO2 (1%) and NiTiO3/TiO2 (1%).
ca b TiO
2 :Ni(1
%)
NiO
x /TiO
2(1
%)
472 470 468 466 464 462 460 458
20000
40000
60000
80000
100000
120000
140000
C
C
A
NiT
iO3 /T
iO2
(1%
)
868 866 864 862 860 858 856 854 852
117000
118000
119000
120000
121000
122000
123000
124000
C
C
A
868 866 864 862 860 858 856 854 852
117000
118000
119000
120000
121000
122000
123000
124000
D
D
A
868 866 864 862 860 858 856 854 852
117000
118000
119000
120000
121000
122000
123000
124000
E
E
A
868 866 864 862 860 858 856 854 852
134000
135000
136000
137000
138000
139000
140000
141000
142000
143000 C
C
A
868 866 864 862 860 858 856 854 852
134000
135000
136000
137000
138000
139000
140000
141000
142000
143000 D
D
A
868 866 864 862 860 858 856 854 852
134000
135000
136000
137000
138000
139000
140000
141000
142000
143000 E
E
A
868 866 864 862 860 858 856 854 852
51600
51800
52000
52200
52400
52600
52800
53000
53200
53400
53600 C
C
A
868 866 864 862 860 858 856 854 852
51600
51800
52000
52200
52400
52600
52800
53000
53200
53400
53600 D
D
A
868 866 864 862 860 858 856 854 852
51600
51800
52000
52200
52400
52600
52800
53000
53200
53400
53600 E
E
A
538 536 534 532 530 528 526
50000
100000
150000
200000
D
D
A
538 536 534 532 530 528 526
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
220000 C
C
A
538 536 534 532 530 528 526
40000
60000
80000
100000
120000
140000
160000
180000 D
D
A
538 536 534 532 530 528 526
40000
60000
80000
100000
120000
140000
160000
180000 C
C
A
538 536 534 532 530 528 526
50000
100000
150000
200000
E
E
A
538 536 534 532 530 528 526
40000
60000
80000
100000
120000
140000
160000
180000 E
E
A
538 536 534 532 530 528 526
20000
30000
40000
50000
60000
70000
80000
90000 D
D
A
538 536 534 532 530 528 526
20000
30000
40000
50000
60000
70000
80000
90000 C
C
A
472 470 468 466 464 462 460 458
20000
30000
40000
50000
60000
70000
80000
90000
100000
110000
120000
130000
140000
150000 D
D
A
472 470 468 466 464 462 460 458
20000
40000
60000
80000
100000
120000 C
C
A
472 470 468 466 464 462 460 458
20000
30000
40000
50000
60000
70000
80000
90000
100000
110000
120000 D
D
A
472 470 468 466 464 462 460 458
10000
20000
30000
40000
50000
60000 C
C
A
472 470 468 466 464 462 460 458
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
55000
60000 D
D
A
868 864 860 856 852
856.0 eV
Ni 2p3/2
Sat.
868 864 860 856 852
Binding Energy (eV)
Ni 2p3/2
Sat.856.07 eV
Inte
nsity (
a.u
.)
Ni 2p3/2
Sat.856.3 eV
537 534 531 528
Binding Energy (eV)
O 1s
533.2 eV
O 1s
531.09 eV
O 1s
534.7 eV
O 1s
531.0 eV
O 1s
533.1 eV
537 534 531 528
O 1s
534.9 eV
O 1s
531.0 eV
O 1s
533.0 eV
Ti 2p1/2
464.5 eV
Ti 2p3/2
459.0 eV
471 468 465 462 459
Ti 2p1/2
464.5 eV
Ti 2p3/2
458.9 eV
Binding Energy (eV)
471 468 465 462 459
Ti 2p1/2
464.4 eV
Ti 2p3/2
458.7 eV
1000 800 600 400 200 0
Inte
nsity (
a.u
.)
NiTiO3/TiO2
NiOx/TiO2
TiO2:Ni
O 1
sT
i 1s
C 1
s
Binding Energy (eV)
Ni 2p
S12
10. TiO2:Ni annealed in argon
Figure S10. TEM image of NiOx/TiO2 (5%) annealed in argon.
Figure S11. XRD pattern of TiO2 and NiOx/TiO2 (1%, 2%, 5%) annealed in argon.
200 nm
20 30 40 50 60 70 80
*
*
*
TiO2 JCPDS:01-073-1764
NiOx/TiO2 (5%)
NiOx/TiO2 (2%)
NiOx/TiO2 (1%)
TiO2Inte
nsity (
a.u
)
2 (Degree)
NiOx
S13
11. Nitrogen adsorption-desorption isotherms
Figure S12. Nitrogen adsorption (open symbols) and desorption (filled symbols) isotherms
measured of (a) NiOx-TiO2(1%) and (b) NiTiO3-TiO2(1%) at 77.3 K.
0.0 0.2 0.4 0.6 0.8 1.0
Adsorption
Desorption
Relative pressure (P/P0)
Qu
an
tity
ad
so
rbe
d (
a.u
.)
BET Specific surface 28.0 m2/g
NiOx-TiO2(1%)
0.0 0.2 0.4 0.6 0.8 1.0
Adsorption
Desorption
Relative pressure (P/P0)
Qu
an
tity
ad
so
rbe
d (
a.u
.)
BET specific surface 40.8 m2/g
NiTiO3-TiO2(1%)
a b
S14
12. NiTiO3 reference material
Figure S13. SEM images of NiTiO3
Figure S14. XRD pattern of NiTiO3
400 nm
20 40 60 80
NiTiO3 JCPDS:01-076-0335Inte
nsity (
a.u
.)
2(Degree)
NiTiO3
S15
13. Literature comparison
Table S2. Comparison of the hydrogen evolution rate and the apparent quantum yield with reported
Ni-Ti-O systems.
Photocatalyst H2 Evolution Rate
μmol h-1 g-1 Reaction conditions AQY %
Ref.
Ni/NiO/N-TiO2-x 185 110W λ˃420nm 7.5 S1
0.23%Ni(OH)2 on TiO2 900 3W 365nm 12.4 S2
0.25wt% NiO-TiO2 261 3W 365nm 1.7 S3
TiO2-Ni(HCO3)2-2.5% 377 300W 380nm (±5nm) 6.24 S4
0.32% Ni(NO3)2-TiO2 163 3W 365nm 8.1 S5
Mesoporous NiO/TiO2 240 3W 365nm 1.7 S6
Pt NiO/TiO21:1 molar ratio
1,250 400W UV 7.8
S7
Hollow NiTiO3/TiO2(1%) 11,500 365nm 11.6 This
work
S16
14. Photocatalytic H2 production rates
Figure S15. Photocatalytic H2 production rates obtained from TiO2, NiTiO3, TiO2:Ni (1%),
NiOx/TiO2 (1%), NiTiO3/TiO2 ( 1%, 2%, 5%).
0
2
4
6
8
10
12
14
16
NiT
iO3/T
iO2 (
5%
)
NiT
iO3/T
iO2 (
2%
)
NiT
iO3/T
iO2 (
1%
)
NiT
iO3/T
iO2 (
0.5
%)
TiO
2
NiO
x/T
iO2 (
5%
)
NiO
x/T
iO2 (
2%
)
NiO
x/T
iO2 (
1%
)
NiO
x/T
iO2 (
0.5
%)
TiO
2:N
i (0
.5%
)
TiO
2:N
i (5
%)
TiO
2:N
i (2
%)
TiO
2:N
i (1
%)
0.2
2.0
0.50.1
1.9
0.50.2
3.4
11.6
2.5
4.4
1.42.1
3.1
NiT
iO3
H2 m
mol h
-1g
-1
S17
15. UV-vis analysis
Figure S16. Kubelka-Munk function for TiO2, NiTiO3/TiO2 (1, 2, 5%) and NiOx/TiO2 including a
linear fit (dashed lines) to determine the band gap energy.
1.5 2.0 2.5 3.0 3.5 4.0
NiTiO3/TiO2
NiTiO3
(1%)
(2%)
(5%)
NiOx/TiO2 (1%)
Energy (eV)
(h)1
/2 / (
eV
/m)1
/2
TiO2
1%, 2%, 5%
S18
References
S1. S. Hu, F. Li, Z. Fan and J. Gui, J. Power Sources, 2014, 250, 30–39. S2. J. Yu, Y. Hai and B. Cheng, J. Phys. Chem. C, 2011, 115, 4953–4958. S3. L. Li, B. Cheng, Y. Wang and J. Yu, J. Colloid Interface Sci., 2015, 449, 115–121. S4. Y. Wei, G. Cheng, J. Xiong, F. Xu and R. Chen, ACS Sustain. Chem. Eng., 2017, 5, 5027–5038. S5. W. Wang, S. Liu, L. Nie, B. Cheng and J. Yu, Phys. Chem. Chem. Phys., 2013, 15, 12033–12039. S6. L. Li, B. Cheng, Y. Wang and J. Yu, J. Colloid. Interf. Sci., 2015, 449, 115-121. S7. A. Rawool, M. R. Pai, A. M. Banerjee, A. Arya, R. Ningthoujam, R. Tewari, R. Rao, B. Chalke, P. Ayyub and A. Tripathi,
Appl. Catal. B Environ., 2018, 221, 443-458.
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