Pyrene-containing conjugated organic microporous polymers for photocatalytic hydrogen evolution from water

Article abstract of DOI:10.1039/d0cy02482a

Photoactive conjugated microporous polymers (CMPs) are emerging as porous materials capable of mediating the photocatalytic evolution of H₂from water. In this study, we synthesized three pyrene-based CMPs (Py-F-CMP, Py-TPA-CMP, Py-TPE-CMP) through Sonogashira-Hagihara cross-couplings of 1,3,6,8-tetraethynylpyrene (Py-T, as a common monomer building block) with 2,7-dibromo-9H-fluorene (F-Br₂), tris(4-bromophenyl)amine (TPA-Br₃), and 1,1,2,2-tetrakis(4-bromophenyl)ethene (TPE-Br₄), respectively, in the presence of Pd(PPh₃)₄in DMF/Et₃N. We then characterized the chemical structures, crystallinities, thermal stabilities, surface morphologies, and porosities of these three new CMPs. Brunauer-Emmett-Teller (BET) analyses and tests of photocatalytic H₂production revealed that Py-TPA-CMP displayed the highest BET surface area (454 m²g^?1), highest total pore volume (0.28 cm³g^?1), highest H₂evolution rate (19?200 μmol h^?1g^?1), and highest apparent quantum yield (15.3%) when compared with those of Py-F-CMP, Py-TPE-CMP, and other organic porous materials.

Full text of DOI:10.1039/d0cy02482a

Catalysis
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PAPER
Pyrene-containing conjugated organic
microporous polymers for photocatalytic
Cite this: Catal. Sci. Technol., 2021,
11, 2229
hydrogen evolution from water†
ab
cd
Mohamed Gamal Mohamed,
‡
Mohamed Hammad Elsayed,‡
c
a
a
Ahmed M. Elewa,
Ahmed F. M. EL-Mahdy,
Cheng-Han Yang,
Ahmed A. K. Mohammed, Ho-Hsiu Chou * and Shiao-Wei Kuo *ae
b
c
Photoactive conjugated microporous polymers (CMPs) are emerging as porous materials capable of
mediating the photocatalytic evolution of H
CMPs (Py–F-CMP, Py–TPA-CMP, Py–TPE-CMP) through Sonogashira–Hagihara cross-couplings of 1,3,6,8-
tetraethynylpyrene (Py–T, as a common monomer building block) with 2,7-dibromo-9H-fluorene (F–Br ),
tris(4-bromophenyl)amine (TPA–Br ), and 1,1,2,2-tetrakis(4-bromophenyl)ethene (TPE–Br ), respectively, in
the presence of Pd(PPh in DMF/Et N. We then characterized the chemical structures, crystallinities,
thermal stabilities, surface morphologies, and porosities of these three new CMPs. Brunauer–Emmett–Teller
BET) analyses and tests of photocatalytic H production revealed that Py–TPA-CMP displayed the highest BET
2
from water. In this study, we synthesized three pyrene-based
2
3
4
)
3 4
3
Received 30th December 2020,
Accepted 20th January 2021
(
2
2
−1
3
−1
surface area (454 m g ), highest total pore volume (0.28 cm g ), highest H
2
evolution rate (19 200 μmol
g ), and highest apparent quantum yield (15.3%) when compared with those of Py–F-CMP, Py–TPE-
CMP, and other organic porous materials.
DOI: 10.1039/d0cy02482a
−
1
−1
h
rsc.li/catalysis
semiconductor materials (e.g., oxysulfides, sulfides, metal
oxides, nitrides) have been used for photocatalytic H evolution
Introduction
2
17–25
Hydrogen (H ) is perhaps the most environmentally friendly
because of their high stability and activity,
these materials
2
and sustainable energy source for solving our energy crisis and
can have their disadvantages, including difficult syntheses,
low-availability of their required metal resources, and narrow
absorption bands. Fujishima and Honda prepared an
1–6
overcoming environmental pollution. The production of H2
can be achieved most simply through photocatalytic water
4–12
splitting.
If a polymeric material is to be used as a
operational photo-electrochemical cell featuring
a
TiO
2
24
photocatalyst for water splitting it should possess the following
features: (i) corrosion-resistance toward water; (ii) suitable
energy levels and structures to facilitate transport of charge
carriers in the polymeric framework; (iii) a suitable band gap to
enhance the capture of visible photons to produce sufficient
carriers to facilitate the reduction of protons; (iv) a suitable
absorption band edge position; and (v) an appropriate surface
electrode for water spitting. In contrast, Wang and co-workers
used g-C N , a highly thermally and chemically stable metal-
3
4
2
5
2
free polymer, as a photocatalyst for H production. The
search for additional materials that can be used in
photocatalytic H production systems has become a hot topic
2
in academia and industry. Organic semiconductor
photocatalysts are particularly attractive because of their
tunable energy band structures, tunable electronic structures,
1
3–18
to catalyze chemical reactions.
Although inorganic
tunable molecular structures, ease of synthesis, and ease of
a
26–28
Department of Materials and Optoelectronic Science, Center of Crystal Research,
functional group modification.
Conjugated microporous
National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
E-mail: kuosw@faculty.nsysu.edu.tw
polymers (CMPs), linear conjugated polymers, covalent
triazine-based frameworks (CTFs), and covalent organic
frameworks (COFs) are all organic polymer materials that have
been tested widely in photocatalysis, supercapacitors, chemical
b
Chemistry Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt
c
Department of Chemical Engineering, National Tsing Hua University, Hsinchu
3
0013, Taiwan. E-mail: hhchou@mx.nthu.edu.tw
d
Department of Chemistry, Faculty of Science, Al-Azhar University, Nasr City
1884, Cairo, Egypt
2 2
sensors, CO uptake, optical devices, and photocatalytic H
29–48
1
production.
materials for gas storage and conversion, drug delivery,
chemical sensing, photocatalysis, photocatalytic CO reduction,
CMPs are particularly interesting emerging
e
Department of Medicinal and Applied Chemistry, Kaohsiung Medical University,
Kaohsiung 807, Taiwan
Electronic supplementary information (ESI) available. See DOI: 10.1039/
d0cy02482a
These authors contributed equally.
2
†
optical devices, energy storage, and light-driven H production,
2
‡
due to their tunable permanent nanoporous structures, ease of
This journal is © The Royal Society of Chemistry 2021
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synthesis, low cost, excellent stability and activity, high surface
areas and porosities, low densities, diverse material
morphologies and compositions, and useful energy level
methanol (MeOH), and chloroform (CHCl ) were purchased
3
from Alfa Aesar. Pd(PPh ) was ordered from Sigma-Aldrich.
3
4
4
9–57
structures, optical band gaps, and photoelectric properties.
Janiak et al. prepared PCTF-8, a CMP that featured a BET
1
,3,6,8-Tetrabromopyrene (Py–Br
4
)
A solution of Br (2.3 mL, 44 mmol) was dissolved in
2
2
−1
surface area (SBET) of 625 m g , a total pore volume of 0.32
nitrobenzene (20 mL) and added to a solution of pyrene (2.00
g, 10 mmol) in nitrobenzene (20 mL). Then the mixture was
refluxed at for 4 h at 120 °C until a green powder was
appeared. The green solid was washed with EtOH, filtered
off, and dried under vacuum at 50 °C under vacuum to Py–
3
−1
−1 −1
cm g , and a H evolution rate (HER) of 1185 μmol h
g
2
when irradiated with light at wavelengths greater than 420
5
8
nm. Cooper et al. reported that the CMP S-CMP3 displayed
−1
−1
HERs of 3106 and 6076 μmol h
g
when irradiated with light
at >420 and 251 nm, respectively, with the apparent quantum
−
1
Br
4
(4.4 g, 89%). FTIR (KBr, cm , Fig. S1†): 3053 (aromatic
53
yield (AQY) reaching 13.2% at 420 nm. Furthermore, Bojdys
C–H stretching), 682 (C–Br stretching).
et al. synthesized SNP-2 and found that this CMP material
−1
−1
provided a HER of 472 μmol h
g
in the presence of Pt and
1,3,6,8-Tetrakis(2-(trimethylsilyl)ethynyl)pyrene (Py–TMS)
triethanolamine (TEOA) when irradiated with light at 395
5
9
nm. Pyrene (Py) moiety possesses extended π-conjugation
Pd(PPh ) (220 mg, 0.120 mmol), PPh (244 mg, 0.920 mmol),
3
4
3
28,60
with planar structure and donor property.
While
and CuI (118 mg, 0.620 mmol) were added to a solution of
3
Py–Br (2.00 g, 2.38 mmol) in dry toluene (28 mL) and Et N
triphenylamine (TPA) and its derivatives have central nitrogen
atom connected with triphenyl groups, excellent hole
4
(28 mL) under N . After heating to 50 °C, TMSA (2.34 g, 23.8
2
6
0
transporting and large steric hindrance. The preparation of
CMPs based on pyrene, triphenylamine, fluorene (F) and
tetraphenylethene (TPE) have been applied as materials in
chemical sensing agents, gas adsorbents water treatment,
energy storage and optoelectronic devices due to their high
specific surface area, easy synthesis, good processability and
mmol) was injected dropwise into the flask and then the
mixture was heated at for 48 h at 90 °C. The solvent was
removed under vacuum to obtain an orange solid.
Temperature for onset of decomposition: 350 °C. FTIR (KBr,
−
1
cm , Fig. S2†): 3053 (aromatic C–H stretching), 2908
(aliphatic C–H stretching), 2100 (CC stretching), 1618
61–66
1
high thermal stability.
To the best of our knowledge, the
(CC stretching). H NMR (500 MHz, CDCl , δ, ppm, Fig.
3
1
3
three types of pyrene functionalized CMPs in this study are
new and no report until now for using these materials for
photocatalytic hydrogen evolution from water. In this study, we
prepared the CMPs Py–F-CMP, Py–TPA-CMP and Py–TPE-CMP
through Sonogashira–Hagihara cross-couplings of 1,3,6,8-
tetraethynylpyrene (as a common monomeric building block)
3
S3†): 0.413 (s, 36H, CH ), 8.3 (s, 2H), 8.57 (s, 4H). C NMR
(600 MHz, CDCl , δ, ppm, Fig. S4†): 135.70, 132.40, 127.80,
3
119.20, 103.50, 101.60.
1,3,6,8-Tetraethynylpyrene (Py–T)
A mixture of Py–TMS (2.00 g, 3.41 mmol), K
2
3
CO (5.70 g, 42.0
2
with 2,7-dibromo-9H-fluorene (F–Br ), tris(4-bromophenyl)
mmol), and anhydrous MeOH (50 mL) was stirred in a one-
neck flask at room temperature for 48 h until an orange
powder was formed. The solid was filtered to obtain Py–T
amine (TPA–Br ), and 1,1,2,2-tetrakis(4-bromophenyl)ethene
3
(
TPE–Br
4
),
respectively,
in
the
presence
of
tetrakis(triphenylphosphine) palladium(0) as the catalyst in N,
(
1.88 g, 94.3%; Scheme S1†). Temperature for onset of
N-dimethylformamide (DMF)/triethylamine (Et N) as the
3
−1
decomposition: 350 °C. FTIR (KBr, cm , Fig. S5†): 3279
solvent. We then used various techniques to determine the
porosities, chemical structures, thermal stabilities, and surface
morphologies of these three CMPs. Finally, we measured their
(
C–H), 3065 (aromatic C–H stretching), 2186 (CC
1
stretching), 1618 (CC stretching). H NMR (500 MHz,
CDCl , δ, ppm, Fig. S6†): 8.68 (s, 4H), 8.38 (s, 2H), 3.67 (s,
3
1
abilities to mediate photocatalytic H
the presence of ascorbic acid (AA) as a sacrificial electron donor
SED) and Pt as a co-catalyst. These three new CMP materials
displayed high H production from water.
2
evolution from water in
3
4
1
3
H). C NMR (125 MHz, CDCl , δ, ppm, Fig. S7†): 133.80,
30.80, 129.10, 127.80, 84.50, 59.70.
(
2
2,7-Dibrmo-9H-fluorene (F–Br2)
FeCl (67.0 mg, 1.20 mmol) and fluorene (2.00 g, 12.0 mmol)
was dissolved in CHCl3 (25 mL) and then the mixture was
cooled in an ice bath at 0 °C. After that, Br solution (1.29
2
3
Experimental
Materials
Pyrene (98%), triphenylamine (TPA, 98%), (trimethylsilyl)
mL, 25.27 mmol) in CHCl (15 mL) was injected dropwise to
3
acetylene
triphenylphosphine (PPh
9%), benzophenone (99%), bromine (Br ), zinc (Zn, 98%),
(98%),
copper(I)
iodide
(CuI,
99%),
the mixture in the dark. The reaction solution was kept and
stirred for at 0 °C for 3 h. Then, saturated aqueous Na S O
2 2 5
3
, 99%), N-bromosuccinimide (NBS,
9
(40 mL) was added to the reaction mixture. The mixture was
extracted with CHCl and organic CHCl was dried (MgSO ),
2
titanium tetrachloride (TiCl4, 99.9%), fluorene (98%),
potassium carbonate (K CO , 99.9%), anhydrous ferric chloride
FeCl , 99.9%), anhydrous Et N (99%), anhydrous magnesium
3
3
4
2
3
filtered, and concentrated under vacuum to obtain F–Br
2
as a
(
colorless solid (3.90 g, 89%: Scheme S2†). M.p.: 164–165 °C
3
3
−
1
sulfate (MgSO4, 99.5%), tetrahydrofuran (THF), acetone,
(DSC, Fig. S8†). FTIR (KBr, cm , Fig. S9†): 3051 (aromatic
2230 | Catal. Sci. Technol., 2021, 11, 2229–2241
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C–H stretching), 2922 (C–H stretching), 1255 (C–O–C
Py–F-CMP
Py–T (100 mg, 0.340 mmol), F–2Br (174 mg, 0.530 mmol), CuI
6.40 mg, 0.0400 mmol), PPh (14.0 mg, 0.0500 mmol), and
1
stretching). H NMR (500 MHz, CDCl , δ, ppm, Fig. S10†):
3
1
3
3
.04 (s, 2H), 6.94 (d, 2H), 7.06 (d, 2H), 7.57 (d, 2H). C NMR
(
3
(
125 MHz, CDCl , δ, ppm, Fig. S11†): 145.30, 139.80, 131.20,
3
Pd(PPh
mL) was degassed twice under vacuum and then stirred at
00 °C for 72 h. The insoluble solid was washed several times
with THF, DMF, and acetone. The dark red powder was dried
3 4 3
) (38.0 mg, 0.0330 mmol) in DMF (5 mL) and Et N (5
1
28.50, 36.50.
1
Tris(4-bromophenyl)amine (TPA–Br
3
)
−
1
at 100 °C (Scheme S5†). FTIR (KBr, cm ): 3062 (aromatic C–H
stretching), 2190 (CC stretching), 1603 (CC stretching).
In a round-bottom flask, NBS (1.00 g, 5.75 mmol) in DMF
(
(
10 mL) was mixed with a solution of triphenylamine (TPA)
0.459 g, 1.87 mmol) in DMF (15 mL) and then the mixture
Py–TPA-CMP
was stirred at room temperature for 24 h. After evaporation
DMF, CH Cl (200 mL) and H O (300 mL) were added to
Py–T (100 mg, 0.340 mmol), TPA–Br
CuI (6.40 mg, 0.0400 mmol), PPh (14.0 mg, 0.0500 mmol),
and Pd(PPh3)4 (38.0 mg, 0.0330 mmol) in DMF (5 mL) and
Et N (5 mL) was degassed twice under vacuum and then
3
(216 mg, 0.330 mmol),
2
2
2
3
the mixture. Then, the organic layer was dried above
MgSO filtered, and concentrated under vacuum. The
4
,
3
residue was washed several times with MeOH to afford
stirred at 100 °C for 72 h. The insoluble solid was filtered off
and washed several times with THF, DMF, and acetone. The
dark red powder was dried at 100 °C (Scheme S6†). FTIR
TPA–Br as a white solid (0.94 g, 90%: Scheme S3†). M.p.: 140–
3
−1
1
(
42 °C (DSC, Fig. S12†). FTIR (KBr, cm , Fig. S13†): 3078
aromatic C–H stretching), 1618 (CC stretching). H NMR
1
−
1
(
KBr, cm ): 3058 (aromatic C–H stretching), 2179 (CC
(
6
500 MHz, CDCl , δ, ppm, Fig. S14†): 6.94 (d, 6H), 7.35 (d,
3
13
stretching), 1583 (CC stretching).
3
H). C NMR (125 MHz, CDCl , δ, ppm, Fig. S15†): 146.80,
133.20, 126.20, 116.40.
Py–TPE-CMP
4
Py–T (150 mg, 0.470 mmol), TPE–Br (215 mg, 0.330 mmol),
Tetraphenylethylene (TPE)
Under N , benzophenone (3.00 g, 16.4 mmol) and Zn (4.31 g,
CuI (9.00 mg, 0.0500 mmol), PPh (13.0 mg, 0.0500 mmol),
3
and Pd(PPh
3 4
) (57.0 mg, 0.0500 mmol) in DMF (5 mL) and
2
6
5.9 mmol) in THF (80 mL) was stirred in ice/salt-water bath
3
Et N (5 mL) was degassed twice under vacuum and then
for 10 min. TiCl (3.60 mL, 33.0 mmol) was injected over 30
min and then the mixture was kept at 80 °C under reflux.
Then, 5% aqueous K CO was added to the reaction. After
2 3
stirred at 100 °C for 72 h. The insoluble solid was filtered off
and washed several times with THF, DMF, and acetone. The
dark red powder was dried at 100 °C (Scheme S7†). FTIR
(KBr, cm ): 3058 (aromatic C–H stretching), 2179 (CC
stretching), 1595 (CC stretching).
4
−
1
evaporation of the organic solvent, the aqueous phase was
extracted three times with EtOAc. After evaporation EtOAc,
the residue was washed with EtOH to obtain a white
crystalline solid (2.66 g, 97%). M.p.: 228–229 °C (DSC, Fig.
Catalyst solution for photocatalytic H evolution
2
−
1
S16†). FTIR (KBr, cm , Fig. S17†): 3047 (aromatic C–H
Py–F-CMP, Py–TPA-CMP, or Py–TPE-CMP was dispersed in
1
stretching), 1602 (CC stretching). H NMR (500 MHz,
water/MeOH (2/1, 10 mL) containing H PtCl (3%) and 0.1 M
2
6
13
CDCl , δ, ppm, Fig. S18†): 7.26 (d, 8H), 6.84 (d, 8H). C NMR
3
AA. The catalyst solution was exposed to light from a 350 W
(
125 MHz, CDCl , δ, ppm, Fig. S19†): 140.70, 141.00, 131.30,
−2
3
Xe lamp (1000 W m ; λ > 420 nm) that had passed through
1
27.70, 126.4.
a 420 nm band-pass filter. The production of H2 was
evaluated through gas chromatography (GC7920), operated
under the isothermal condition by the semi-capillary column
equipped with the thermal conductivity detector. The AQY
was calculated using the following equations:
1
,1,2,2-Tetrakis(4-bromophenyl)ethene (TPE–Br4)
A solution of TPE (3.32 g, 10.0 mmol) in glacial acetic acid
(
(
10 mL) and CH Cl (20 mL) in a round-bottom flask at 0 °C
2 2
ice bath). Br (4.00 mL, 80.0 mmol) was added to the mixture
2
number of evolved H2 molecules × 2 Ne
and the mixture was kept at room temperature for 48 h.
AQY ¼
¼
(1)
number of incident photons
Np
Then, the H O (200 mL) was added to the resulting solution
2
2
M × NA 2M × NA 2M × NA × h × c
and the mixture was extracted with CH
2 2
Cl . After evaporation
¼
¼
¼
× 100%
Etotal
S × P × t
c
h ×
λ
S × P × t × λ
CH Cl , the residue was washed with MeOH to give a white
Ephoton
2
2
solid (Scheme S4†), which was recrystallized (CH Cl /MeOH)
2
2
to give TPE–Br
4
as a white crystalline solid (6.15 g, 95%). M.p.:
where NA
is the Avogadro constant, M is the amount of H
2
−1
261–262 °C (DSC, Fig. S20†). FTIR (KBr, cm , Fig. S21†):
produced (mol), c is the speed of light h is the Planck
1
2
3
051 (aromatic C–H stretching), 1572 (CC stretching).
, δ, ppm, Fig. S22†): 7.25 (d, 8H), 6.84
d, 8H). C NMR (125 MHz, CDCl , δ, ppm, Fig. S23†):
H
constant,
S
is the irradiation area (cm ),
t
is the
NMR (500 MHz, CDCl
(
3
photoreaction time (s), P is the intensity of the irradiating
13
−2
light (W cm ), and λ is the wavelength of the monochromatic
3
142.30, 139.70, 133.70, 131.90, 121.80.
light (m).
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Scheme 1 Synthesis of (a) Py–F-CMP, (b) Py–TPA-CMP, and (c) Py–TPE-CMP through Sonogashira–Hagihara cross-couplings.
Results and discussion
118.53 ppm for Py–TPA-CMP, and 142.19–118.68 ppm for Py–
TPE-CMP. In addition, signals of the carbon nuclei of the
internal alkynyl bonds of Py–F-CMP, Py–TPA-CMP and Py–
TPE-CMP appeared centered at 80.82, 81.95, and 81.39 ppm,
Schemes S1–S4† display the routes followed for the
preparation of Py–T, TPE–Br , TPA–Br , and F–Br . The CMPs
4 3 2
Py–F-CMP, Py–TPA-CMP, and Py–TPE-CMP were obtained as
red solids in high yields through Sonogashira–Hagihara
cross-couplings between Py–T (as the common monomer
1
3
respectively. The C NMR spectrum of Py–F-CMP [Fig. 2(a)]
featured a signal centered at 49.38 ppm for the methylene
groups in this framework.
building block) and F–Br
respectively, in the presence of Pd(PPh ) in DMF/Et N over
2
,
TPA–Br
3
,
and TPE–Br
4
,
We used thermogravimetric analysis to examine the
thermal stabilities of Py–F-CMP, Py–TPA-CMP, and Py–TPE-
3
4
3
7
2 h at 100 °C under a N
2
atmosphere (Scheme 1). All the
CMP under
a
N
2
atmosphere (Fig. 3). The thermal
resulting CMP materials are insoluble in DMF, MeOH, EtOH,
THF, CH Cl , DMSO, and acetone. The chemical structures of
degradation temperatures Td5 and Td10 of Py–F-CMP were 187
and 321 °C, respectively; for Py–TPA-CMP they were 306 and
382 °C, respectively; and for Py–TPE-CMP they were 295 and
358 °C, respectively. Py–F-CMP, Py–TPA-CMP, and Py–TPE-
CMP displayed char yields of 54, 70, and 64%, respectively.
The powder X-ray diffraction (PXRD) patterns of these CMPs
did not feature any crystalline peaks or long-range order (Fig.
S24†), suggesting that each of these materials had
amorphous character. We used field-emission scanning
electron microscopy (FE-SEM) to examine the surface
morphologies of Py–F-CMP, Py–TPA-CMP, and Py–TPE-CMP
(Fig. S25†). The surface morphology of Py–F-CMP featured
fused rod-like particles, while Py–TPA-CMP and Py–TPE-CMP
presented fused irregularly aggregated spherical particles.
The BET specific surface areas (SBET), pore diameters, and
total pore volumes (Vtotal) of Py–F-CMP, Py–TPA-CMP and Py–
2
2
all the synthesized monomers and of Py–F-CMP, Py–TPA-
1
13
CMP, and Py–TPE-CMP were confirmed using H and
C
1
3
NMR spectroscopy, solid state C NMR spectroscopy, and
FTIR spectroscopy. The DSC, FTIR and NMR spectra revealed
2 3 4
that F–Br , TPA–Br , TPE and TPE–Br had been obtained
with high purity (Fig. S8–S23†). Fig. 1 presents the FTIR
spectra of Py–T, Py–F-CMP, Py–TPA-CMP, and Py–TPE-CMP.
The FTIR spectrum of Py–T [Fig. 1(a)] features absorption
−
1
bands at 3279, 3053, 2186, and 1618 cm , corresponding to
its H–CC, C–H aromatic, CC, and CC units,
respectively. Fig. 1(b–d) reveals that the signals for the
vibrations of the aromatic rings in Py–F-CMP, Py–TPA-CMP,
and Py–TPE-CMP appeared clearly in the range 3087–3044
−
1
cm , while those for the CC units appeared in the range
−
1
2
190–2185 cm . Moreover, the large decreases in the
TPE-CMP were characterized through N measurements at 77
2
intensities of the absorption bands for the terminal alkynyl
K (Fig. 4). The BET analyses [Fig. 4(a–c)] revealed type IV
curves, suggesting mesoporous structures for these three
CMP polymers; furthermore, Fig. 4(b) revealed microporous
behavior for Py–TPA-CMP, identified by a sharp rise at
−
1
groups (H–CC) near 3279 cm in the FTIR spectra of Py–F-
CMP, Py–TPA-CMP, and Py–TPE-CMP confirmed that their
polymeric condensations had occurred with high degrees of
1
3
polymerization. Solid state C NMR spectroscopy [Fig. 2(a–c)]
revealed signals for the carbon nuclei of the aromatic units
in the ranges 141.22–120.77 ppm for Py–F-CMP, 146.08–
relatively low pressure (P/P
0
= 0–0.1). Furthermore, the values
2
−1
of S and Vtotal for Py–F-CMP were 191 m
g
and 0.06
BET
−1
3
2
−1
cm g , respectively; for Py–TPA-CMP they were 454 m g
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Fig. 1 FTIR spectra of (a) Py–T, (b) Py–F-CMP, (c) Py–TPA-CMP, and (d) Py–TPE-CMP, recorded at 25 °C.
1
3
Fig. 2 Solid-state C CP/MAS NMR spectra of (a) Py–F-CMP, (b) Py–TPA-CMP, and (c) Py–TPE-CMP, recorded at 25 °C. Asterisks denote spinning
sidebands.
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3
−1
and 0.28 cm g , respectively; and for Py–TPE-CMP they were
2
−1
3
−1
1
82 m g and 0.13 cm g , respectively. We used nonlocal
density functional theory (NL-DFT) to evaluate the pore
diameters of the CMPs [Fig. 4(d–f)]. Based on their pore size
distribution curves, the pore diameters of Py–F-CMP, Py–TPA-
CMP, and Py–TPE-CMP were 2.14–2.85, 1.21–2.53, and 2.60
nm, respectively. TEM images [Fig. 4(g–j)] revealed that these
three porous polymers possessed micro/mesoporous
structures with uniform pore sizes (1.5–2.5 nm). Based on the
TGA and BET data, the thermal stability, surface area, and
total pore volume of Py–TPA-CMP were all higher than those
of Py–F-CMP and Py–TPE-CMP.
We recorded UV-vis diffuse reflectance spectra (DRS) to
determine whether the CMPs had optical band gaps suitable
for use as photocatalysts; Fig. 5 presents the effective
photocatalytic performance of these three polymers. As
revealed in Fig. 5(a), all of these polymers absorbed visible
light well in the range 350–585 nm. Notably, the signals in
Fig. 3 TGA analyses of Py–F-CMP, Py–TPA-CMP, and Py–TPE-CMP.
Fig. 4
N
2
adsorption/desorption isotherms of (a) Py–F-CMP, (b) Py–TPA-CMP, and (c) Py–TPE-CMP. Pore size distribution curves of (d) Py–F-CMP,
(
e) Py–TPA-CMP, and (f) Py–TPE-CMP. TEM images of (g) Py–F-CMP, (h) Py–TPA-CMP, and (j) Py–TPE-CMP.
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2
Fig. 5 (a) UV-vis DRS spectra and (b) Tauc plots of (αhν) versus (hν), derived from the UV-vis spectral data and by extrapolation from the linear
1/2
part of the curve to the energy axis based on the equation αhν = A(hν − E
g
)
, of Py–F-CMP, Py–TPA-CMP, and Py–TPE-CMP.
the spectrum of Py–TPA-CMP were slightly red-shifted when
compared with those of Py–F-CMP and Py–TPE-CMP,
presumably because of the presence of its TPA units. The
optical band gaps of Py–F-CMP, Py–TPA-CMP, and Py–TPE-
CMP, calculated from Tauc plots [Fig. 5(b)] were 1.83, 1.80,
and 1.85 eV, respectively (Table 1).
Fig. S26† presents the results of photoelectron
spectroscopy, revealing that the highest occupied molecular
orbitals (HOMOs) of Py–F-CMP, Py–TPA-CMP, and Py–TPE-
CMP had energies of 5.65, 5.55, and 5.68 eV, respectively
water production; therefore, we believed that our three new
CMPs would function as photocatalysts for light-driven H2
evolution. We measured the HER of Py–TPA-CMP in the
presence of AA, TEOA, and TEA triethylamine as SEDs, while
adding MeOH into the Py–TPA-CMP/H O system to enhance
2
the miscibility [Fig. 6(a)]. Py–TPA-CMP displayed good
photocatalytic performance in the presence of AA as the SED,
with HERs 10-fold and more than 100-fold greater than those
obtained using TEOA and TEA, respectively. We optimized
various factors to obtain the best conditions for the
photocatalytic reaction, including the amount of the
photocatalyst, the concentration of Pt co-catalyst, and the
concentration of AA as the SED. Fig. 6(b) reveals the effect of
(Table 1); their corresponding lowest unoccupied molecular
orbitals (LUMOs) had energies of 3.82, 3.75, and 3.83 eV,
respectively (Table 1), calculated from the expression EHOMO
−
E (where E was determined using the Tauc plot method).
The UV-vis DRS data suggested that each of these
polymers had LUMO energy higher than the potential of
the amount of Py–TPA-CMP on the H evolution performance
in the presence 0.1 M AA. The HER increased upon
increasing the amount of Py–TPA-CMP from 0.5 to 3 mg, but
g
g
2
2
Table 1 Photophysical properties and H evolution data of the three polymers
Absorption
[nm]
HOMO/LUMO
[eV]
Band gap
[eV]
AQY% at 420 nm
d,e
a,b
c
−1
−1 −1
Polymer
HER [μmol h
]
HER [μmol h
g
]
(at 460 nm) [%]
Py–TPA-CMP
Py–TPE-CMP
Py–F-CMP
360 to 585
360 to 558
360 to 565
−5.55/−3.75
−5.68/−3.83
−5.65/−3.82
1.80
1.85
1.83
57.5
39.1
16.8
19 200
13 033
5600
15.3
6.3
2.3
a
b
c
HOMO determined using photoelectron spectroscopy. LUMO derived from the expression EHOMO − E
g
.
Calculated from the Tauc plot of
e
2
d
−2
(αhν) versus (hν). Conditions: photocatalyst (3 mg), 0.2 M AA, 3% H
2
PtCl
6
, and 350 W Xe lamp (1000 W m ; λ > 420 nm). AQYs measured
at 420 and 460 nm.
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−2
2
Fig. 6 (a) Effect of SEDs on photocatalytic H production under visible light mediated by Py–TPA-CMP (1 mg); 350 W Xe lamp (1000 W m ; λ >
−
2
4
20 nm). (b) Effect of photocatalyst concentration in the presence of 0.1 M AA; 350 W Xe lamp (1000 W m ; λ > 420 nm). (c) Effect of H
2
6
PtCl as
−
2
a co-catalyst in the presence of Py–TPA-CMP dose (3 mg) and 0.1 M AA; 350 W Xe lamp (1000 W m ; λ > 420 nm). (d) Effect of AA concentration
−2
in the presence of Py–TPA-CMP (3 mg); 350 W Xe lamp (1000 W m ; λ > 420 nm).
it decreased thereafter upon increasing the amount of the
CMP to 5 mg, suggesting that the optimum amount of Py–
TPA-CMP in this system photocatalytic reaction was 3 mg.
Furthermore, the HER of Py–TPA-CMP was enhanced the
most in the presence of H PtCl when using 3% of this co-
μmol) and Py–F-CMP (69.1 μmol). Fig. 7(b) and Table 1
display the calculated HERs of our CMPs. The promising
−
1
HER of Py–TPA-CMP (57.5 μmol h ) was higher than those of
−
1
−1
Py–TPE-CMP (39.1 μmol h ) and Py–F-CMP (16.8 μmol h ). We
attribute the highest HER of Py–TPA-CMP to its high value of
2
6
2
−1
3
−1
catalyst [Fig. 6(c)]. Although Fig. 6(d) reveals that the rate of
production of Py–TPA-CMP also increased upon increasing
SBET (454 m g ), its high total pore volume (0.28 cm g ) and
H
2
its red-shifted UV-vis spectral absorption bands, which enhanced
the capture of visible light. In addition, the Py–TPA-CMP
contains pyrene as strong electron donating group and TPA as
strong electron-accepting unit which can be enhanced the
charge separation, and electron transfer ability in the Py–
TPA-CMP. Also, the presence of N atom in the TPA units acts
as hole traps and provide reactive sites which facilitating hole
the AA concentration, we select a concentration of AA of 0.2
M in our subsequent experiments for ready comparison with
the results of previous studies. Under the optimal conditions
(
3 mg of the polymer, 3% Pt, and 0.2 M AA), we compared
the performance of the three polymers Py–F-CMP, Py–TPA-
CMP, and Py–TPE-CMP as photocatalysts for H evolution
2
under irradiation with visible light (λ > 420 nm) at room
temperature. As revealed in Fig. 7(a), the amount of
transfer, charge separation and enhanced H generation from
2
67–69
water.
To evaluate the photocatalytic activity of our
evolution, we also measured
generated H
2
reached a maximum value of 231.7 μmol after 6
photocatalysts for light driven H
2
h when using Py–TPA-CMP as the photocatalyst; this value
was higher than those obtained using Py–TPE-CMP (201.9
the H2 evolution from our photocatalytic system in the
absence of AA as the SED and also in the absence of the
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Fig. 7 (a) Time course of the production of H
2
mediated by the three polymers. (b) HERs of the three polymers; conditions: photocatalyst (3 mg),
−
2
0
.2 M AA, 3% H
2 6
PtCl , and 350 W Xe lamp (1000 W m ; λ > 420 nm). (c) AQYs of the Py–TPA-CMP at various wavelengths of light. (d) AQYs of the
three polymers under light at 420 nm, measured under the optimized conditions at ambient temperature; conditions: photocatalyst (3 mg), 0.2 M
−
2
2 6
AA, 3% H PtCl , and 350 W Xe lamp (1000 W m ; λ > 420 nm).
photocatalyst. As displayed in Fig. S27,† no H2 production
occurred in the absence of AA, light, or polymer under
otherwise identical conditions, confirming the necessity of
each for a successful photocatalytic process in this system. We
also estimated the AQYs of Py–TPA-CMP [Fig. 7(c)] at
wavelengths of 420, 460, 500, 550, and 600 nm, obtaining
values of 15.3, 11.1, 10.7, 4.5, and 2.1%, respectively. At 420
nm, the AQYs of Py–C-CMP, Py–TPA-CMP, and Py–TPE-CMP
were 2.5, 15.3, and 6.3%, respectively [Fig. 7(d)]. Ren et al.
reported that Ta-CMP-CN, which featured terminal electron
highest photocatalytic efficiencies and displayed promising
AQYs. We employed density functional theory (DFT) to
examine the electronic states of our three new polymers. The
ground state geometries of the three monomers were
optimized using the B3LYP functional with the D3BJ
correction and the basis set 6-31G(d). This dispersion
correction is necessary to account for long-range and
72,73
noncovalent interactions.
Fig. 8 reveals that, for each of
the three polymers, both HOMO and LUMO are extended all
over the conjugated system. Fig. S28–S30† presented the
excited states of the Py–F-CMP, Py–TPA-CMP and Py–TPE-
CMP, and their contribution of the transition between
orbitals. In addition, Fig. 8 reveals that, for Py–F-CMP and
Py–TPE-CMP, the HOMO and LUMO are extended all over the
conjugated system. This indicates the complete overlapping
for HOMO and LUMO, leads to increasing the recombination
of excited electrons. In contrast in the case of Py–TPA-CMP,
−1
−1
withdrawing groups, provided a HER (698 μmol g h , with
an AQY of 0.15%) under visible light that was higher than that
−
1
−1 70
of Ta-CMP-N (99 μmol g h ). Wang and co-workers found
−1 71
that the HER of L-PyBT was 87.7 μmol h . Table S1†
summarizes the HER performances and AQYs of our CMPs
and those of the previously reported microporous polymer
photocatalysts; among them, our polymers achieved the
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Fig. 8 Main transitions between orbitals that compose the predominant exited state of Py–F-CMP, Py–TPA-CMP and Py–TPE-CMP along with the
percentage contribution of each transition.
the LUMO is distributed mostly over the pyrene units, and a
lesser extent to TPA unit. Thus, the HOMO and LUMO are
partially separated leading to decreasing the recombination
Thus, our CMPs function as photocatalysts with promising
production efficiencies and very high stability.
H
2
of excited electrons and enhancing the photocatalytic Conclusion
efficiency. We tested the stability and recycling of Py–TPA-
We have synthesized three CMPs—Py–F-CMP, Py–TPA-CMP,
CMP and Py–TPE-CMP as photocatalysts under irradiation
with visible light (λ > 420 nm) (Fig. S31†). These materials
maintained approximately the same performance, in terms of
and Py–TPE-CMP—based on pyrene moieties through simple
and environmentally friendly Sonogashira–Hagihara cross-
1
3
couplings. FTIR and solid state C NMR spectra confirmed
their chemical structures. TGA revealed that Py–TPA-CMP had
a thermal degradation temperature (358.0 °C) and char yield
H
2
production rate, over three cycles (18 h) without
decreasing the photocatalytic efficiency. Finally, we have
performed FTIR and UV-vis measurements, and field-
emission scanning electron microscopy (FE-SEM) to check
the stability of the chemical structure and surface
morphology of Py–F-CMP, Py–TPA-CMP and Py–TPE-CMP
after photocatalysts measurements. As shown in FTIR spectra
(
70%) higher than those of Py–F-CMP, Py–TPE-CMP, and
other porous materials. Furthermore, Py–TPA-CMP provided
−
1
−1
a HER of 19 200 μmol h g , with a high AQY of 15.3% that
was higher than those of Py–F-CMP and Py–TPE-CMP,
2
−1
presumably because of its high surface area (454 m g ),
(
Fig. S32†), the three new polymers showed absorption bands
3
−1
−1
−1
high total pore volume (0.28 cm g ), suitable band gap, and
presence of nitrogen heteroatoms.
in the range 3051–3065 cm , 2200–2191 cm , and 1603–
1
−1
585 cm , corresponding to their C–H aromatic, CC, and
CC, respectively. In addition, the absorption bands of Py–F-
CMP, Py–TPA-CMP and Py–TPE-CMP were slightly blue-
shifted after photocatalysts measurements, as presented in
Fig. S33 .† Based on SEM images after photocatalysts
measurements (Fig. S34†), the surface morphologies of Py–F-
CMP, Py–TPA-CMP, and Py–TPE-CMP featured fused rod-like
particles. The results above showed that our three polymers
could maintain their structure after photocatalytic reaction.
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
This study was supported financially by the Ministry of
Science and Technology, Taiwan, under contracts MOST108-
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2
2
638-E-002-003-MY2, 108-2221-E-110-014-MY3 and MOST 109-
636-E-007-021. The authors acknowledge generous
14 T. X. Wang, H. P. Liang, D. A. Anito, X. Ding and B. H. Han,
Emerging applications of porous organic polymers in visible-
light photocatalysis, J. Mater. Chem. A, 2020, 8, 7003–7034.
15 C. L. Chang, W. C. Lin, C. Y. Jia, L. Y. Ting, J. Jayakumar,
M. H. Elsayed, Y. Q. Yang, Y. H. Chan, W. S. Wang, C. Y. Lu,
P. Y. Chen and H. H. Chou, Low-toxic cycloplatinated
polymer dots with rational design of acceptor co-monomers
for enhanced photocatalytic efficiency and stability, Appl.
Catal., B, 2020, 268, 118436.
a
allocation of computer time granted by Compute Canada
national HPC platform. The authors thank to the staff at
National Sun Yat-sen University for assistance with TEM (ID:
EM022600) experiments.
Notes and references
1
L. Hammarström and S. Hammes-Schiffer, Artificial
Photosynthesis and Solar Fuels, Acc. Chem. Res., 2009, 42,
16 S. Luo, Z. Zeng, G. Zeng, Z. Liu, R. Xiao, P. Xu, H. Wang, D.
Huang, Y. Liu, B. Shao, Q. Liang, D. Wang, Q. He, L. Qin
and Y. Fu, Recent advances in conjugated microporous
polymers for photocatalysis: designs, applications, and
prospects, J. Mater. Chem. A, 2020, 8, 6434.
17 W. H. Wang, L. Y. Ting, J. Jayakumar, C. L. Chang, W. C. Lin,
C. C. Chung, M. H. Elsayed, C. Y. Lu, A. M. Elewa and H. H.
Chou, Design and synthesis of phenylphosphine oxide-based
polymer photocatalysts for highly efficient visible-light-
driven hydrogen evolution, Sustain, Energy Fuels, 2020, 4,
5264–5270.
18 W. C. Lin, M. H. Elsayed, J. Jayakumar, L. Y. Ting, C. L.
Chang, A. M. Elewa, W. S. Wang, C. C. Chung, C. Y. Lu and
H. H. Chou, Design and synthesis of cyclometalated iridium-
based polymer dots as photocatalysts for visible light-driven
hydrogen evolution, Int. J. Hydrogen Energy, 2020, 45,
32072–32081.
1
859–1860.
2
3
Y. Tachibana and L. Vayssieres, Artificial photosynthesis for
solar water-splitting, Nat. Photonics, 2012, 6, 511.
J. Zhang, Y. Chen and X. C. Wang, Two-dimensional covalent
carbon nitride nanosheets: synthesis, functionalization, and
applications, Energy Environ. Sci., 2015, 8, 3092–3108.
Z. A. Lan, W. Ren, X. Chen, Y. F. Zhang and X. C. Wang,
Conjugated donor-acceptor polymer photocatalysts with
electron-output “tentacles” for efficient hydrogen evolution,
Appl. Catal., A, 2019, 245, 596–603.
4
5
M. Karayilan, W. P. Brezinski, K. E. Clary, D. L.
Lichtenberger, R. S. Glass and J. Pyun, Catalytic
Metallopolymers
Metalloenzymes for Hydrogen Production, Angew. Chem.,
019, 131, 7617–7630.
from
[2Fe-2S]
Clusters:
Artificial
2
6
7
K. Mazloomi and C. Gomes, Hydrogen as an energy carrier:
Prospects and challenges, Renewable Sustainable Energy Rev.,
19 R. Asahi, T. Morikawa, H. Irie and T. Ohwaki, Nitrogen-
Doped
Titanium
Dioxide
as
Visible-Light-Sensitive
2
012, 16, 3024–3033.
Photocatalyst: Designs, Developments, and Prospects, Chem.
Rev., 2014, 114, 9824–9852.
M. H. Elsayed, J. Jayakumar, M. Abdellah, T. H. Mansoure,
K. Zheng, A. M. Elewa, C. L. Chang, L. Y. Ting, W. C. Lin,
H. H. Yu, W. H. Wang, C. C. Chung and H. H. Chou, Visible-
light-driven hydrogen evolution using nitrogen-doped
carbon quantum dot-implanted polymer dots as metal-free
photocatalysts, Appl. Catal., B, 2021, 283, 119659.
M. G. Walter, E. L. Warren, J. R. McKone, S. W. Boettcher, Q.
Mi, E. A. Santori and N. S. Lewis, Solar Water Splitting Cells,
Chem. Rev., 2010, 110, 6446–6473.
L. Y. Ting, J. Jayakumar, C. L. Chang, W. C. Lin, M. H.
Elsayed and H. H. Chou, Effect of controlling the number of
fused rings on polymer photocatalysts for visible-light-driven
hydrogen evolution, J. Mater. Chem. A, 2019, 7, 22924–22929.
20 L. Liu, Z. Ji, W. Zou, X. Gu, Y. Deng, F. Gao, C. Tang and L.
Dong, In Situ Loading Transition Metal Oxide Clusters on
2
TiO Nanosheets As Co-catalysts for Exceptional High
Photoactivity, ACS Catal., 2013, 3, 2052–2061.
21 X. Chen, S. Shen, L. Guo and S. S. Mao, Semiconductor-
based Photocatalytic Hydrogen Generation, Chem. Rev.,
2010, 110, 6503–6570.
22 A. Kudo and Y. Miseki, Heterogeneous photocatalyst
materials for water splitting, Chem. Soc. Rev., 2009, 38,
253–278.
8
9
23 L. Liu, X. Gu, Z. Ji, W. Zou, C. Tang, F. Gao and L. Dong,
2
Anion-Assisted Synthesis of TiO Nanocrystals with Tunable
1
0 P. Kumar, R. Boukherroub and K. Shankar, Sunlight-driven
water-splitting using two-dimensional carbon-based
Crystal Forms and Crystal Facets and Their Photocatalytic
Redox Activities in Organic Reactions, J. Phys. Chem. C,
2013, 117, 18578–18587.
semiconductors, J. Mater. Chem. A, 2018, 6, 12876–12931.
1 L. Cheng, Q. Xiang, Y. Liao and H. Zhang, CdS-Based
photocatalysts, Energy Environ. Sci., 2018, 11, 1362–1391.
2 A. F. M. EL-Mahdy, A. M. Elewa, S. W. Huang, H. H. Chou
and S. W. Kuo, Dual-Function Fluorescent Covalent Organic
Frameworks: HCl Sensing and Photocatalytic H2 Evolution
from Water, Adv. Opt. Mater., 2020, 8, 2000641.
1
1
24 A. Fujishima and K. Honda, Electrochemical Photolysis of
Water at a Semiconductor Electrode, Nature, 1972, 238, 37–38.
25 X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M.
Carlsson, K. Domen and M. Antonietti,
A metal-free
polymeric photocatalyst for hydrogen production from water
under visible light, Nat. Mater., 2009, 8, 76.
1
3 J. Wang, G. Ouyang, Y. Wang, X. Qiao, W. S. Li and H. Li,
26 R. S. Sprick, J. X. Jiang, B. Bonillo, S. Ren, T. Ratvijitvech, P.
Guiglion, M. A. Zwijnenburg, D. J. Adams and A. I. Cooper,
Tunable Organic Photocatalysts for Visible-Light-Driven
Hydrogen Evolution, J. Am. Chem. Soc., 2015, 137,
3265–3270.
1
,3,5-Triazine and dibenzo[b,d]thiophene sulfone based
conjugated porous polymers for highly efficient
photocatalytic hydrogen evolution, Chem. Commun.,
020, 56, 1601.
2
This journal is © The Royal Society of Chemistry 2021
Catal. Sci. Technol., 2021, 11, 2229–2241 | 2239

View Article Online
Paper
Catalysis Science & Technology
2
7 M. G. Mohamed, C. C. Lee, A. F. M. EL-Mahdy, J. Luder,
M. H. Yu, Z. Li, Z. Zhu, C. C. Chueh and S. W. Kuo,
Exploitation of Two-Dimensional Conjugated Covalent
Organic Frameworks Based on Tetraphenylethylene with
Bicarbazole and Pyrene Units and Applications in Perovskite
Solar Cells, J. Mater. Chem. A, 2020, 8, 11448–11459.
8 M. G. Mohamed, A. F. M. EL-Mahdy, Y. Takashi and S. W.
Kuo, Ultrastable conductive microporous covalent triazine
frameworks based on pyrene moieties provide high-
performance CO2 uptake and supercapacitance, New J.
Chem., 2020, 44, 8241–8253.
39 M. M. Samy, M. G. Mohamed and S. W. Kuo, Directly
synthesized
nitrogen-and-oxygen–doped
microporous
carbons derived from
a
bio-derived polybenzoxazine
exhibiting high-performance supercapacitance and CO2
uptake, Eur. Polym. J., 2020, 138, 109954.
40 L. Li, Z. Cai, Q. Wu, W. Y. Lo, N. Zhang, L. X. Chen and L.
Yu, Rational design of porous conjugated polymers and roles
of residual palladium for photocatalytic hydrogen
production, J. Am. Chem. Soc., 2016, 138, 7681–7686.
41 M. G. Mohamed, A. F. M. EL-Mahdy, M. M. M. Ahmed and
S. W. Kuo, Direct Synthesis of Microporous Bicarbazole-
Based Covalent Triazine Frameworks for High-Performance
Energy Storage and Carbon Dioxide Uptake, ChemPlusChem,
2019, 84, 1767–1774.
42 D. J. Woods, R. S. Sprick, C. L. Smith, A. J. Cowan and A. I.
Cooper, A solution-processable polymer photocatalyst for
hydrogen evolution from water, Adv. Energy Mater., 2017, 7,
1700479.
2
2
9 M. G. Mohamed, E. C. A. Jr, B. M. Matsagar, J. Na, Y.
Yamauchi, K. C. W. Wu and S. W. Kuo, Construction
Hierarchically Mesoporous/Microporous Materials Based on
Block Copolymer and Covalent Organic Framework,
J. Taiwan Inst. Chem. Eng., 2020, 112, 180–192.
3
3
3
0 V. S. Vyas, F. Haase, L. Stegbauer, G. Savasci, F. Podjaski, C.
Ochsenfeld and B. V. Lotsch, A tunable azine covalent
organic framework platform for visible light-induced
hydrogen generation, Nat. Commun., 2015, 6, 8508–8516.
1 A. F. M. EL-Mahdy, M. Y. Lai and S. W. Kuo, Highly
fluorescent covalent organic framework as hydrogen
chloride sensor: Roles of Schiff base bonding and
π-stacking, J. Mater. Chem. C, 2020, 8, 9520–9528.
43 A. F. M. El-Mahdy, M. G. Mohamed, T. H. Mansoure, H. H.
Yu, T. Chen and S. W. Kuo, Ultrastable tetraphenyl-p-
phenylenediamine-based covalent organic frameworks as
platforms
for
high-performance
electrochemical
supercapacitors, Chem. Commun., 2019, 55, 14890–14893.
44 C. B. Meiera, R. S. Sprick, A. Montib, P. Guiglion, J. S. M.
Lee, M. A. Zwijnenburg and A. I. Cooper, Structure–property
relationships for covalent triazine-based frameworks: the
effect of spacer length on photocatalytic hydrogen evolution
from water, Polymer, 2017, 126, 283–290.
45 L. Wang, Y. Wan, Y. Ding, S. Wu, Y. Zhang, X. Zhang,
G. Zhang, Y. Xiong, X. Wu, J. Yang and H. Xu,
Conjugated microporous polymer nanosheets for overall
water splitting using visible light, Adv. Mater., 2017, 29,
1702428.
2 A. F. M. EL-Mahdy, C. H. Kuo, A. Alshehri, C. Young, Y.
Yamauchi, J. Kim and S. W. Kuo, Strategic design of
triphenylamine-
and
triphenyltriazine-based
two-
dimensional covalent organic frameworks for CO2 uptake
and energy storage, J. Mater. Chem. A, 2018, 6, 19532–19541.
3 Y. Yu, N. Mao, S. Feng, C. Zhang, F. Wang, Y. Chen, J. Zeng
and J. X. Jiang, Perylene-Containing Conjugated
Microporous Polymers for Photocatalytic Hydrogen
Evolution, Macromol. Chem. Phys., 2017, 218, 1700049.
4 C. Krishnaraj, H. S. Jena, K. Leus and P. V. D. Voort,
Covalent triazine frameworks a sustainable perspective,
Green Chem., 2020, 22, 1038–1071.
3
3
3
46 V. S. Vyas, F. Haase, L. Stegbauer, G. Savasci, F. Podjaski, C.
Ochsenfeld and B. V. Lotsch, A tunable azine covalent
organic framework platform for visible light-induced
hydrogen generation, Nat. Commun., 2015, 6, 8508.
5 X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M.
Carlsson, K. Domen and M. Antonietti,
polymeric photocatalyst for hydrogen production from water
under visible light, Nat. Mater., 2009, 8, 76–80.
A
metal-free
47 M. G. Mohamed, N. Y. Liu, A. F. M. EL-Mahdy and S. W.
Kuo, Ultrastable luminescent hybrid microporous polymers
based on polyhedral oligomeric silsesquioxane for CO2
uptake and metal ion sensing, Microporous Mesoporous
Mater., 2021, 311, 110695.
48 T. Sick, A. G. Hufnagel, J. Kampmann, I. Kondofersky, M.
Calik, J. M. Rotter, A. Evans, M. Döblinger, S. Herbert, K.
Peters, D. Böhm, P. Knochel, D. D. Medina, D. F. Rohlfing
and T. Bein, Oriented films of conjugated 2D covalent
organic frameworks as photocathodes for water splitting,
J. Am. Chem. Soc., 2018, 140, 2085–2092.
3
6 A. F. M. El-Mahdy, C. Young, J. Kim, J. You, Y. Yamauchi and
S. W. Kuo, Hollow microspherical and microtubular [3+3]
carbazole-based covalent organic frameworks and their gas
and energy storage applications, ACS Appl. Mater. Interfaces,
2
019, 11(9), 9343–9354.
3
7 B. P. Biswal, H. A. Vignolo-González, T. Banerjee, L.
Grunenberg, G. Savasci, K. Gottschling and B. V. Lotsch,
Sustained Solar
H
2
Evolution from a Thiazolo[5,4-d]
thiazole-Bridged Covalent Organic Framework and Nickel-
Thiolate Cluster in Water, J. Am. Chem. Soc., 2019, 141,
49 P. Pachfule, A. Acharjya, J. Roeser, T. Langenhahn, M.
Schwarze, R. Schomäcker, A. Thomas and J. Schmidt,
Diacetylene functionalized covalent organic framework
(COF) for photocatalytic hydrogen generation, J. Am. Chem.
Soc., 2018, 140, 1423–1427.
50 M. Sachs, R. S. Sprick, D. Pearce, S. A. J. Hillman, A. Monti,
A. A. Y. Guilbert, N. J. Brownbill, S. Dimitrov, X. Shi, F.
Blanc, M. A. Zwijnenburg, J. Nelson, J. R. Durrant and A. I.
1
1082–11092.
3
8 A. F. M. EL-Mahdy, Y. H. Hung, T. H. Mansoure, H. H. Yu,
Y. S. Hsu, K. C. W. Wu and S. W. Kuo, Synthesis of [3+3]
β-ketoenamine-tethered covalent organic frameworks (COFs)
for high-performance supercapacitance and CO2 storage,
J. Taiwan Inst. Chem. Eng., 2019, 103, 199–208.
2240 | Catal. Sci. Technol., 2021, 11, 2229–2241
This journal is © The Royal Society of Chemistry 2021

View Article Online
Catalysis Science & Technology
Paper
Cooper, Understanding structure-activity relationships in
linear polymer photocatalysts for hydrogen evolution, Nat.
Commun., 2018, 9, 4968.
transport material triphenylamine derivatives, J. Lumin.,
2017, 124, 333–342.
62 M. M. Samy, M. G. Mohamed and S. W. Kuo, Pyrene-
functionalized tetraphenylethylene polybenzoxazine for
dispersing single-walled carbon nanotubes and energy
storage, Compos. Sci. Technol., 2020, 199, 108360.
5
5
5
1 Y. Xiang, X. Wang, L. Rao, P. Wang, D. Huang, X. Ding, X.
Zhang, S. Wang, H. Chen and Y. Zhu, Conjugated Polymers
with Sequential Fluorination for Enhanced Photocatalytic H
2
Evolution via Proton-Coupled Electron Transfer, ACS Energy
Lett., 2018, 10, 2544–2549.
2 X. Wang, B. Chen, W. Dong, X. Zhang, Z. Li, Y. Xiang and
63 L. Lan, F. Liu, Y. Dan and L. Jiang, Facile fabrication of
triphenylamine-based conjugated porous polymers and their
application in organic degradation under visible light, New J.
Chem., 2020, 44, 2986–2995.
H.
Microporous Polymers for Enhanced Visible-Light-Driven
Photocatalytic Evolution, Macromol. Rapid Commun.,
019, 40, 1800494.
Chen,
Hydrophilicity-Controlled
Conjugated
64 Q. Zhang, S. Yu, Q. Wang, Q. Xiao, Y. Yue and S. Ren,
H
2
Fluorene-Based
Conjugated
Microporous
Polymers:
2
Preparation and Chemical Sensing Application, Macromol.
Rapid Commun., 2017, 38, 1700445.
3 R. S. Sprick, Y. Bai, A. A. Y. Guilbert, M. Zbiri, C. M.
Aitchison, L. Wilbraham, Y. Yan, D. J. Woods, M. A.
Zwijnenburg and A. I. Cooper, Photocatalytic Hydrogen
65 M. G. Mohamed, A. F. M. EL-Mahdy, T. S. Meng, M. M. Samy
and S. W. Kuo, Multifunctional Hypercrosslinked Porous
Organic Polymers Based on Tetraphenylethene and
Triphenylamine Derivatives for High-Performance Dye
Adsorption and Supercapacitor, Polymers, 2020, 12, 2426.
66 M. G. Mohamed, M. Y. Tsai, C. F. Wang, C. F. Huang, M.
Danko, L. Dai, T. Chen and S. W. Kuo, Multifunctional
Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid
Evolution
from
Water
Using
Fluorene
and
Dibenzothiophene Sulfone-Conjugated Microporous and
Linear Polymers, Chem. Mater., 2019, 2, 305–313.
5
5
4 G. Zhang, Z. A. Lan and X. Wang, Conjugated Polymers:
Catalysts for Photocatalytic Hydrogen Evolution, Angew.
Chem., Int. Ed., 2016, 55, 15712–15727.
5 C. Dai, L. Zhong, X. Gong, L. Zeng, C. Xue, S. Li and B. Liu,
Triphenylamine based conjugated microporous polymers for
selective photoreduction of CO2 to CO under visible light,
Green Chem., 2019, 21, 6606–6610.
2
Porous Materials for CO Uptake and Iodine Adsorption,
Polymers, 2021, 13, 221.
67 S. Bhattacharyya, F. Ehrat, P. Urban, R. Teves, R. Wyrwich,
M. Döblinger, J. Feldmann, A. S. Urban and J. K. Stolarczyk,
Effect of nitrogen atom positioning on the trade-off between
emissive and photocatalytic properties of carbon dots, Nat.
Commun., 2017, 8, 1401.
68 C. Dai and B. Liu, Conjugated polymers for visible-light-
driven photocatalysis, Energy Environ. Sci., 2020, 13, 24–52.
69 J. Yu, X. Sun, X. Xu, C. Zhang and X. He, Donor-Acceptor
Type Triazine-based Conjugated Porous Polymer for Visible-
Light-Driven Photocatalytic Hydrogen Evolution, Appl. Catal.,
B, 2019, 257, 117935.
5
5
5
6 K. I. Aly, M. M. Sayed, M. G. Mohamed, S. W. Kuo and O.
Younis, A facile synthetic route and dual function of network
luminescent porous polyester and copolyester containing
porphyrin moiety for metal ions sensor and dyes adsorption,
Microporous Mesoporous Mater., 2020, 298, 110063.
7 M. G. Mohamed, X. Zhang, T. H. Mansoure, A. F. M. EL-
Mahdy, C. F. Huang, M. Danko, Z. Xin and S. W. Kuo,
Hypercrosslinked porous organic polymers based on
tetraphenylanthraquinone for CO
2
uptake and high-
performance supercapacitor, Polymer, 2020, 205, 122857.
70 K. Ding, Q. Zhang, Q. Li and S. Ren, Terminal Group Effect
of Conjugated Microporous Polymers for Photocatalytic
Water-Splitting Hydrogen Evolution, Macromol. Chem. Phys.,
2019, 220, 1900304.
8 A. Bhunia, D. Esquivel, S. Dey, R. Fernandez-Teran, Y. Goto,
S. Inagaki, P. Van der Voort and C. Janiak,
A
photoluminescent covalent triazine framework: CO
2
adsorption, light-driven hydrogen evolution and sensing of
nitroaromatics, J. Mater. Chem. A, 2016, 4, 13450–13457.
9 D. Schwarz, Y. S. Kochergin, A. Acharjya, A. Ichangi, M. V.
Opanasenko, J. Cejka, U. Lappan, P. Arki, J. He, J. Schmidt,
P. Nachtigall, A. Thomas, J. Tarabek and M. J. Bojdys, Chem.
71 C. Cheng, X. Wang, Y. Lin, L. He, J. X. Jiang, Y. Xu and F.
Wang, The effect of molecular structure and fluorination on
the properties of pyrene-benzothiadiazole-based conjugated
polymers for visible-light-driven, Polym. Chem., 2018, 9,
4468–4475.
72 S. Grimme, J. Antony, S. Ehrlich and H. Krieg, A consistent
and accurate ab initio parametrization of density functional
dispersion correction (DFT-D) for the 94 elements H-Pu,
J. Chem. Phys., 2010, 132, 154104.
5
6
6
–
Eur. J., 2017, 23, 13023–13027.
0 Y. Xu, N. Mao, C. Zhang, X. Wang, J. Zeng, Y. Chen, F. Wang
and J. X. Jiang, Rational design of donor-π-acceptor
conjugated microporous polymers for photocatalytic
hydrogen production, Appl. Catal., B, 2018, 228, 1–9.
1 B. C. Wang, H. R. Liao, J. C. Chang, L. Chen and J. T. Yeh,
Electronic structure and molecular orbital study of hole-
73 A. D. Becke and E. R. Johnson, Exchange-hole dipole
moment and the dispersion interaction revisited, J. Chem.
Phys., 2007, 127, 154108.
This journal is © The Royal Society of Chemistry 2021
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