Supporting Information Charge separation and interfacial selectivity induced by synergistic effect of ferroelectricity and piezoelectricity on PbTiO 3 monocrystalline nanoplates Yawei Feng, a,b,c Mengjiao Xu, a Hui Liu, a Wei Li, d Hexing Li, a and Zhenfeng Bian a, * a MOE Key Laboratory of Resource Chemistry and Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai, 200234, P.R. China b CAS Center for Excellence in Nanoscience, Beijing Key S1
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Supporting Information
Charge separation and interfacial selectivity induced by
synergistic effect of ferroelectricity and piezoelectricity
other organics (MB, MO, AR50, BPA) was sonicated for 15 s, and then transferred
into a quartz reactor. The photocatalytic reaction was initiated by a UV LED (CEL-
LED100, 365 nm, 15 mW/cm2) at a certain stirring velocity applied by a magnetic
stirrer. After UV illumination, the sample was centrifuged at 9000 rpm to remove the
photocatalyst particles. The concentration of remaining organics was analyzed by a
UV spectrophotometer (UV 7504/PC) at the characteristic wavelength.
Photocatalytic H2 generation:30 mg photocatalyst was suspended in 30 mL water solution with alcohol (20 vol%)
in 50 mL quartz cell and the suspension was sonicated for 15 s. Then, the cell was
sealed and purged with Ar gas for 20 min. The sample was irradiated with a UV
monochromator (Lamplic GUV-310; 85 mW·cm-2, irradiation area: 0.8 cm2) with
constant magnetic stirring at room temperature. After irradiation, 1 mL of gas was
analyzed using a gas chromatograph (CEAULIGHT, GC-7900) equipped with an MS-
5A column and a thermal conductivity detector.
S5
Figure S1. (a) The band structure of a general semiconductor, ferroelectrics without and with the compressive stress modulation. EC, EV, Ef represent the conduction band, valence band and Fermi level of the given ferroelectric semiconductor, respectively. (b) The proposed principle of facet-depended photocatalysis on PMNs by coupling of ferroelectricity and piezoelectricity.
S6
Figure S2. XPS of P25 and PMNs. High-resolution XPS spectra of (a) C 1s, (b) O 1s,
(c) Ti 2p recorded on P25 and PMNs. High-resolution spectrum of (d) Pb 4f for
PMNs is also shown.
Figure S3. XRD pattern of PMNs.
Figure S4. SEM image of a large-scale PMNs.
S7
Figure S5. AFM topography. (a) The topographic image of a single PMN, (b) shows
the corresponding line profile of the PMN in (a).
Figure S6. A simulation diagram for the orientation of PMNs crystal.
S8
Figure S7. Absorbance spectrum. Absorbance spectrum of PMNs as the function of
(a) wavelength and (b) photon energy. The spectrum was obtained by converting the
UV-vis diffused reflectance spectrum using Kubelka-Munk function.
Suppose the PMNs can be well contacted to ITO glass, the probability of [001]
zone axis of PMNs facing to and backing to ITO glass are equal, thus the band
structure of PMNs is symmetric (Figure S6a). Before any electric poling, the electrode
gives the current output of 4.5 μA/cm2 under UV irradiation (Figure 3a), implying the
obtained PMNs with good response for UV light. After electric poling, the band
structure of PMNs was modulated by the residual polarization due to the ferroelectrics
PMNs are electret. Under the driven of residual polarization, photo-excited hole-
electron pairs can be separated effectively. As for the positive poling (Figure S6b), the
downward band of PMNs at the interface of IFO is more favorable for the migration
of electron to ITO, thus the photocurrent output increases to 5.2 μA/cm2 (Figure 3a).
However, the upward band of PMNs at the interface of IFO (Figure S6c) is less
advantage for the migration of electron to ITO, thus the output decreases to 4.0
μA/cm2 after the electrode being negatively polarized.
Figure S8. Schematic energy band diagrams. Energy band of PMNs (a) at the original
state, (b) being positively polarized and (c) negatively polarized, respectively.
S9
Figure S9. Photocurrent output from P25 electrode before and after poling.
Figure S10. RhB concentration change in PMNs and RhB (10 mg/L) aqueous mixture
in the static state.
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Figure S11. RhB degradation over PMNs in the dark condition. (a) Degradation
performance of RhB induced by piezocatalysis under different stirring speeds and (b)
the fitted quasi-first-order dynamic curve.
Figure S12. The (a) photocatalytic RhB (10 ppm) degradation and (b) quasi-first-
order dynamic curves of under static and stirring state (200 rpm).
S11
Figure S13. RhB degradation over PMNs. (a) The structure illustration of RhB
molecule and (b) the degradation performance of 10 mg/L RhB upon PMNs under
different stirring conditions.
Figure S14. Active species capturing. Degradation performance of RhB under UV
illumination and stirring at 800 rpm with the addition of radical scavenger. (5 mg/L
RhB, 1 mM EDTA-2Na, 1 mM t-BuOH and 1 mM AgNO3 was added, N2 bubbling
for 60 min) The addition of tert-butanol (t-BuOH) as hydroxyl radicals (·OH)
scavenger, EDTA-2Na as holes (h+) scavenger, AgNO3 as electrons (e-) scavenger and
N2 to inhibit the formation of superoxide anions (·O2-).
S12
N
SN N
Figure S15. Structure illustration of MB molecule.
Figure S16. BPA degradation over PMNs. (a) The structure illustration of BPA
molecule. It implies BPA molecule is not ionic molecule. (b) The degradation
performance of 10 mg/L BPA upon PMNs under different stirring conditions.
Structure illustration of molecule.
Figure S17. AR50 degradation. (a) The structure of AR50 molecule and (b) the
degradation performance of 5 mg/L AR50 upon PMNs under different stirring
conditions.
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0 20 40 60 800
2
4
6
8
10M
O c
once
ntra
tion
(mg/
L)
Time (min)
200 rpm 800 rpm
Figure S18. MO degradation. Degradation performance of 10 mg/L MO on 1 wt%
Au-loaded PMNs under different stirring conditions, showing the trend of decreasing
degradation activity can be reduced but cannot be eliminated.
Figure S19. SEM images of PMNs with photo-deposited Pd nanoparticles. The
contents of deposited Pd are (a-c) 1 wt% and (d-f) 2.5 wt%, respectively.
S14
Figure S20. SEM images of PMNs with photo-deposited Pt nanoparticles. The
contents of deposited Pt are (a-c) 3 wt% and (d-f) 5 wt%, respectively.
Figure S21. SEM images of PMNs with NaBH4-reduced Pd nanoparticles. (a-b) The
contents of deposited Pd are 2.5 wt%.
Figure S22. SEM images of PMNs with NaBH4-reduced Pt nanoparticles. (a-b) The
contents of deposited Pt are 3wt%.
S15
Figure S23. XPS spectra of Pt. Fine XPS scan of (a) Pt 4f7 and (b) Pt 4d5 recorded
on PMNs loaded with Pt nanoparticles reduced by NaBH4 and photo method.
Figure S24. Photocatalytic H2 generation at 1600 rpm as a function of irradiation time
in (a) water and (b)20 vol% alcohol aqueous solution over PMNs with Pt loaded by
photo reduction method (red line) and by NaBH4 reduction method (dark line). The
content of Pt is 1 wt%.
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1 2 3 4 5 60
20
40
60
80
H2
gene
ratio
n (μ
mol
)
Cycled number
Figure S25. The durability for H2 generation after each 1 h at 1600 rpm in 20 vol%
alcohol aqueous solution over PMNs with Pt loaded by photo reduction method. The