Metallophthalocyanine-based redox active metal-organic conjugated microporous polymers for OER catalysis

Article abstract of DOI:10.1039/c8cc01291a

We report the design and synthesis of two Co²⁺ and Zn²⁺ phthalocyanine (PC)-based redox active metal-organic conjugated microporous polymers (MO-CMP), CoCMP and ZnCMP, respectively, obtained by a Schiff base condensation reaction. CoCMP, where Co²⁺ is stabilized by N4-coordination of PC, has shown stable and efficient electrocatalytic activity towards the OER with a low overpotential of 340 mV.

Full text of DOI:10.1039/c8cc01291a

View Article Online
View Journal
ChemComm
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: A. Singh, S. Roy,
C. Das, D. Samanta and T. K. Maji, Chem. Commun., 2018, DOI: 10.1039/C8CC01291A.
Volume 52 Number
1
4
January 2016 Pages 1–216
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
ChemComm
Chemical Communications
www.rsc.org/chemcomm
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1359-7345
COMMUNICATION
Marilyn M. Olmstead, Alan L. Balch, Josep M. Poblet, Luis Echegoyenet al.
Reactivity differences of Sc
first methanofullerene derivatives of Sc
3
N@C2n (2n
=
68 and 80). Synthesis of the
3
N@D5h-C80
rsc.li/chemcomm

Page 1 of 4
Please d
C
o
h
n
e
o
m
t a
C
d
o
just margins
m
m
View Article Online
DOI: 10.1039/C8CC01291A
Journal Name
COMMUNICATION
Metallophthalocyanine based redox active metal-organic
conjugated microporous polymers for OER catalysis
Received 00th January 20xx,
Accepted 00th January 20xx
Ashish Singh, Syamantak Roy, Chayanika Das, Debabrata Samanta and Tapas Kumar Maji*
DOI: 10.1039/x0xx00000x
www.rsc.org/
2
+
2+
We report the design and synthesis of two Co and Zn
phthalocyanine (PC) based redox active metal-organic conjugated
microporous polymers (MO-CMP), CoCMP and ZnCMP
respectively, obtained by Schiff base condensation reaction.
2
+
CoCMP, where Co is stabilized by N4-coordination of PC, has
shown stable and effcient electrocatalytic activity towards OER
with a low overpotential of 340 mV.
Conjugated microporous polymer (CMP) materials are derived
from π-conjugated aromatic building block. Owing to the
porosity, these materials have been extensively used for
1
energy storage, catalysis, sensing etc.
Recently, CMP Scheme 1. Synthesis of metal-organic conjugated microporous polymer (MO-CMP);
materials decorated with metal ions have attracted significant CoCMP and ZnCMP.
attention due to the metal driven applications of the resulting
2
metal-organic conjugated microporous polymers (MO-CMP).
designed and synthesized two new redox active MO-CMP
materials (CoCMP and ZnCMP) by integrating them to develop
electrocatalysts for water oxidation, which is an important half
cell reaction for the energy devices like metal-air batteries and
Phthalocyanines (PCs) are nitrogen rich redox active
conjugated macrocycle, possessing N4-coordination site for
3
metal ion. The planar and rigid N4-coordination provides high
9
regenerative fuel cells. However, the sluggish reaction kinetics
stability to the metal ion and makes them easily accessible for
4
various metal based applications. Metallophthalocyanines
of the oxygen evolution reaction (OER) due to the involvement
of four electrons in the reaction mechanism is the main
have therefore been used extensively for energy harvesting
1
0
5
and catalysis. Han and co-workers have reported Co
2+ obstacle in the water oxidation. Therefore, design and
synthesis of an OER electrocatalyst with low over potential and
fast reaction kinetics with high stability is of paramount
phthalocyanine based CMPs as an efficient photosensitizer for
2
a
the singlet oxygen generation. PCs are also well known
1
1
5
a
importance. Transition metal ions, particularly redox active
2
electron donors and with integration of electron acceptors,
redox active donor-acceptor systems can be realized. On the
other hand, oligo-(p-phenyleneethynylenes) (OPEs) are a class
of π-conjugated linear organic chromophores which possess
+
Co ion based materials have drawn immense interest for
designing OER catalysts due to its multiple stable redox
1
2
states. These materials were mainly prepared by Co doping
in the porous organic polymer or by pyrolizing organic-
6
phenyl rings connected through rigid alkyne bonds. Notably,
1
3, 11a
inorganic hybrid material.
However, metal doping
the linear and highly conjugated backbones of OPEs are
7
advantageous for the facile charge transport. Our group has
strategy is associated with the drawbacks of leaching as well as
difficulties in the quantitative control of the metal ion that
eventually affects both activity and stability of the catalyst.
Recently, Das and co-workers have reported “ship in a bottle
strategy” for designing a metal organic framework (MOF)
reported that a suitable alkyl chain substitution on the OPE
backbone alters the physical state, ranging from liquid
8
crystallinity, gels to dispersible materials. The side chains of
OPE backbone also plays a crucial role in regulating the
nanoscale morphology of the resulting material.
5
b
2+
based OER catalyst. Here, the mononuclear Co complex
was locked in the confined space inside the MOF and acts as a
catalytic centre.
Considering
the
individual
advantages
of
the
metallophthalocyanine macrocycle and OPE linker, we have
In this communication, we report the design, synthesis and
characterization of two new MO-CMP based OER catalysts. The
2
+
2+
Molecular Materials Laboratory, Chemistry and Physics of Materials Unit,
amount of Co in CoCMP and Zn in ZnCMP was quantified by
ICP, EDX, and XPS, and found to be 1.7 and 1.5%, respectively.
Both the polymers showed stable charge separated state at
Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560064, India
E-mail: tmaji@jncasr.ac.in;
Tel: 91-8022082826
Electronic Supplementary Information (ESI) available: DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 2 of 4
View Article Online
DOI: 10.1039/C8CC01291A
COMMUNICATION
Journal Name
°
6.2 (d = 3.40 Å) in ZnCMP corresponds to the interlayer
2
separation and indicate the presence of strong π...π stacking in
°
= 4.6 (d
both the compounds. A peak at low angle region of 2
°
θ
19.19 Å) in CoCMP and 4.9 (d = 18.02 Å) in ZnCMP
=
correspond to the distance between two metal centre of the
PC units bridged by the OPE linkers and also indicates the semi
crystalline nature of both the polymers. Thermogravimetric
analysis suggests high thermal stability for both the
compounds (Figure S5). After initial weight loss which
corresponds to the solvent molecules, both MO-CMPs show
°
thermal stability up to 300 C without any significant weight
loss. Surface morphology of CoCMP was studied using FESEM
and TEM by making dispersion of the polymer in ethanol.
FESEM analysis showed the formation of semi spherical
morphology which aggregates to form fractal like structures
2
Fig. 1. Characterization of MO-CMP compounds; (A) PXRD and (B) CO adsorption data
at 195K of CoCMP and ZnCMP, (C) FESEM and (D) TEM image of CoCMP (E) EDX analysis
of CoCMP.
(
Figure 1C). Energy dispersive X-ray (EDX) measurement
indicated the presence of 1.7% cobalt (II) in the polymer
Figure 1E). High resolution TEM analysis showed layered
(
room temperature as realized by EPR spectroscopy. This was
further supported by density functional theory (DFT)
morphology (Figure 1D) which was also found in low resolution
TEM as well (Figure S6). XPS analysis of CoCMP further
confirmed the presence of Co, C, N, and O elements in the
framework (Figure 2A and S7). The XPS spectrum of Co can be
deconvoluted into two components. The Co 2p XPS peaks at
2
+
calculation. Notably, the intrinsically encapsulated Co ion in
the organic framework was found to be the catalytic centre for
the OER. In the electrochemical OER study of CoCMP, an
anodic peak started at 1.57 V that accounts for an
overpotential of 340 mV. The role of permanent porous rigid
framework was examined and found to be essential in
preventing the metallophthalocyanine aggregation and
consequently increase the catalytic performance and
7
73.8 and 800.2 eV can be assigned to 2p
1
and 2p1/2
,
3/2
5, 11b
respectively (Figure 2A).
Three different peaks of C1s
spectrum at 278.0, 285.6 and 286.7 eV indicate the presence
of three different types of carbon and can be attributed to C-C,
C-N/C-O and C=C/C=N, respectively. The peak at 532.1 eV in
the O 1s spectrum confirms the presence of the alkoxy side
chain (C-O-C) of the OPE-5. XPS survey spectra of N 1s shows
three bands; 386.8 eV for imine C=N, 401.6 eV for nitrogen
which connects two pyrrole rings in the PC and 409.5 eV for
metal coordinated pyrrole nitrogen. The amount of metal ions
was further quantified by ICP experiment. ICP-AES data
2
a
2+
stability. The Zn containing MO-CMP was found to be
inactive towards OER catalysis. This clearly explained the
2
importance of Co ion for the OER catalysis.
+
Both the MO-CMPs (CoCMP and ZnCMP) were synthesized by
2
a
schiff
metallophthalocyanine tetraamine and a newly synthesized
,4'-(2,5-bis(pentyloxy)-1,4-phenylene)bis(ethyne-2,1-diyl)
base
condensation
reaction
between
4
2
+
2+
revealed the presence 1.7% of Co and 1.5% of Zn ion in
CoCMP and ZnCMP, respectively.
dibenzaldehyde (OPE-5)) (Scheme 1 and Figure S1-S2).
Obtained MO-CMPs were characterized by elemental analysis,
powder X-ray diffraction (PXRD), thermogravimetric analysis
To analyse the porous nature of these polymers, we carried
out the adsorption study (Figure 1B). Both the polymers were
activated at 140 °C under vacuum for 8 h before performing
the gas adsorption measurement. Both the MO-CMPs showed
(
TGA), field emission scanning electron microscopy (FESEM),
1
transmission electron microscopy (TEM), infrared (IR) and C-
3
1
NMR. Porous nature of the materials was confirmed by the
4
type II adsorption profile for N at 77 K (Figure S8). However,
2
CO adsorption experiment. The similar FTIR spectra of both
2
type I adsorption profile for CO at 195 K (1 atm pressure)
2
the compounds were expected due to the similar functionality
-1
(Figure S3). A very intense peak at 1610 cm was found in both
the compounds. This is apparently characteristic of the
formation of polymer via imine bond (-C=N) formation.
2
M =N)
+
Importantly, a peak in the fingerprint region at 830 (
a
ν
ensured the presence of metal ion in the PC ring. A peak at
2
-
1
2
5
206 cm is attributed to the alkyne bond (-C
1
≡
unit. The solid state C NMR was performed for ZnCMP
C-) of the OPE-
3
(
Figure S4). The most important imine carbon (-C=N-) peak is
found at 156.0 ppm which confirms the polymer formation.
The alkyl (-CH ) and alkoxy (-OCH ) carbons peaks were found
n
2
at 18.6 and 60.1 ppm, respectively, which confirm the
presence side chain of the OPE-5. The carbon of the
heterocycle ring of PC appears deshielded at 167.8 ppm. The
°
value 2-35 (Figure
Fig. 2. (A) XPS peak correspond to Co(II) in CoCMP, (B) EPR spectrum of CoCMP in solid
PXRD was performed within the range of 2
°
θ
state (C) DFT calculations show HOMO on cobalt phthalocyanine (bottom) and LUMO
1A). The broad peak at 2θ= 26.7 (d = 3.30 Å) in CoCMP and on the OPE backbone (top) of CoCMP.
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 4
ChemComm
Please do not adjust margins
View Article Online
DOI: 10.1039/C8CC01291A
Journal Name
COMMUNICATION
1
2
1
2
1.85
(
A)
(B)
I
d
2
= 12.7 mA/cm at 1.84 V vs RHE
(C)
.80 Tafel slope = 87 mV/decade
10
10
Onset potential = 1.57 V vs RHE
Overpotential = 1.57-1.23
= 340 mV
1
1
1
8
6
4
2
0
8
6
4
2
0
2
.75
.70
CoCMP LSV at 50 mV/s 1600 rpm
1.65
1.60
1.55
CoCMP CV at 50 mV/s
-
0
.8 1.0 1.2 1.4 1.6 1.8
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
-1.5 -1.0 -0.5 0.0
log j
0.5
1.0
E
(V)
E
(V)
RHE
RHE
5
4
3
2
1
0
1
2
(
D)1
(E)
(F)
1
4.4
st cycle
000th cycle
st
cycle
10
1
1
th
CoCMP
CoPC
ZnCMP
100 cycle
8
6
4
2
0
9
4
0
.6
.8
.0
1
.4
1.5
1.6
RHE
1.7
(V)
1.8
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
(V)
1.4
1.5
1.6
E
RHE
1.7
(V)
1.8
1.9
E
E
RHE
Fig. 3. Related OER activity for CoCMP, ZnCMP and CoPC: A) CV, B) LSV and C) corresponding Tafel plot of CoCMP D) 1000 cycles of LSV of CoCMP in 0.1 M KOH at scan rate of 50
mV/s and rotation speed of 1600 rpm, E) LSV comparing CoCMP, ZnCMP and Co-PC, F)100 cycles of LSV of Co-PC.
-
demonstrated the micro-porosity in both the compounds. indicated that the electron transfer occurs from HOMO of OH
Both MO-CMPs showed around 25-28 cc/g CO uptake and the to the LUMO of MO-CMPs (Figure S10B).
2
Langmuir surface area of the CoCMP and ZnCMP were found Electrocatalytic performance of both the MO-CMPs towards
2
to be 106.47 and 101.34 m /g, respectively. The non-inclusion OER was studied by cyclic voltammetry (CV) and linear sweep
of N and poor CO uptake can be attributed to the long alkyl voltammetry (LSV) in a three-electrode cell configuration in 0.1
2
2
chain of the OPE-5 occupied pore surface.
M KOH. The CV of CoCMP, at a scan rate of 50 mV/s and
Electron paramagnetic resonance (EPR) study was performed rotation speed of 1600 rpm (Figure 3A) showed onset of water
with both the MO-CMPs in the solid state. In the CoCMP, a oxidation at a potential of 1.57 V. The LSV (Figure 3B) at the
broad signal at g = 2.25 is attributed to the low spin Co(II) same scan rate and rotation speed also showed an onset at
complex (Figure 2B). A sharp and intense signal at g = 4.37 is a 1.57 V with a lower overpotential of 340 mV which is
5
b
triplet marker, indicating the presence of two cobalt PC units comparable to the present state-of-art electrocatalysts. A
1
6
2
in close proximity. This intimates the presence of π...π maximum current of 13 mA/cm was obtained at a potential of
stacking in the polymer in an eclipsed fashion. Notably, a sharp 1.84 V. The linear region in the corresponding Tafel slope
peak at g = 1.99 in CoCMP and g = 2.00 in ZnCMP (Figure S9), (Figure 3C) showed a slope of 87 mV/decade. The low Tafel
represent the redox active nature of polymers and indicates slope and the lower overpotential, explains the fast and the
1
7
the formation of stable charge separated species. Further, to facile kinetics of the oxidation process. Stability and cyclability
get more insight about the charge separated behavior, we of the CoCMP were examined by chronoamperometry (CA)
have performed density functional theory (DFT) computations and LSV, respectively. The chronoamperometric curve
for both CoCMP and ZnCMP. The electron donation property recorded at an applied potential of 1.75 V for 12 h (Figure S12),
of metallophthalocyanine is well documented, however, we showed an initial increase in the current density followed by a
wanted to explore the acceptance property of the conjugated gradual decrease with 91% retention of current density. The
OPE backbone. In CoCMP, the highest occupied molecular initial increase of current density was probably due to the
orbital (HOMO) was situated on the Co-PC units. The energy activation of the surface of the electrocatalyst. During the OER,
difference between the HOMO and lowest unoccupied an insulating layer of oxygen bubbles were observed on the
molecular orbital (LUMO) on the OPE backbone was found to electrode surface, which obstructs the diffusion of charges and
1
3a
be 2.17 eV (Figure 2C). This suggested that PC is the donor and consequently decreases the current density. As prompted
OPE is the acceptor in this donor-acceptor stable charge by the 1000 cycles of LSV (Figure 3D), there was an
separated system. In ZnCMP, the similar electronic infinitesimal increase in the activity of CoCMP after 1000
distributions were found with the energy difference of 2.19 eV cycles which again might be due to the activation of the
(Figure S10A). The energy difference indicated semiconducting catalyst surface. Roughness factor (RF) gave an estimate of the
nature of the highly conjugated polymer that could be electrochemically active surface area (ECSA) which in turn was
effective in electrocatalytic activity. Furthermore, the DFT reflected in the activity of the catalyst. To interpret the
-
O) and hydroxide ion (OH ) infinitesimal increase in the activity, we calculated RF of the
calculation of the water (H
2
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 4 of 4
View Article Online
DOI: 10.1039/C8CC01291A
COMMUNICATION
Journal Name
st
th
catalyst before 1 cycle and after the 1000 cycle and it was (Project No. MR-2015/001019 and Project No. TRC-
found to be 154 and 157, respectively (Figure S11) which DST/C.14.10/16-2724, JNCASR), Govt. of India and JNCASR for
explains the possible activation of the catalyst surface and financial support.
consequently justifies the increase in the current density.
Another parameter that testifies the performance of a catalyst
Conflicts of interest
1
is its turnover frequency (TOF). TOF of CoCMP was calculated
8
There are no conflicts to declare.
1
9, 18
following the reported procedure,
both after the first cycle
th
and the 1000 cycle of LSV and was found to be 0.29 s and
-1
-1
Notes and references
0.20 s , respectively.
1
. (a) A. I. Cooper, Adv. Mater., 2009, 21, 1291; (b) V. M.
To attest the role of metal ion in the catalysis, we performed
2
+
Suresh, A. Bandyopadhyay, S. Roy, S. K. Pati and T. K. Maji,
Chem. Eur. J., 2015, 21, 10799; (c) V. M. Suresh, S. Bonakala, S.
Roy, S. Balasubramanian and T. K. Maji, J. Phys. Chem. C, 2014,
the water oxidation using Zn containing ZnCMP as well. LSV
of ZnCMP (Figure 3E) showed no catalytic activity towards
2
+
OER. Hence it can be inferred that presence of Co dictates
the decent electrocatalysis shown by CoCMP. The next Soc. Rev., 2013, 42, 8012
1
18, 24369; (d) Y. Xu, S. Jin, H. Xu, A. Nagai and D. Jiang, Chem.
2
(
.
b) S. M. J. Rogge, A. Bavykina, J. Hajek, H. Garcia, A. I. Olivos-
(a) X. Ding and B.-H. Han, Angew. Chem. Int. Ed., 2015, 54, 1;
question in our mind was the necessity of the framework. To
answer this, we studied the OER with the discrete Co-
phthalocyanine (Co-PC) unit as the electrocatalyst. The LSV of
Co-PC (Figure 3F) at same experimental conditions showed a
Suarez, A. Sepulveda-Escribano, A. Vimont, G. Clet, P. Bazin, F.
Kapteijn, M. Daturi, E. V. Ramos-Fernandez, F. X. L. Xamena, V.
V. Speybroeck and J. Gascon, Chem. Soc. Rev., 2017, 46, 3134
diminished current density at 1.85 V. The onset was at 1.70 V 3. H. Jia, Y. Yao, J. Zhao, Y. Gao, Z. Luo and P. Du, J. Mater.
Chem. A, 2018, DOI: 10.1039/c7ta07978h.
(a) F. D’Souza and O. Ito, Chem. Soc. Rev., 2012, 41, 86; (b) G.
d. l. Torre, C. G. Claessens and T. Torres, Chem. Commun., 2007,
with overpotential of 470 mV. The declined catalytic activity of
Co-PC could presumably be due to aggregation of the Co-PC
4
.
2
a
units which may restrict an effective accessibility of the
active sites. A rigid and conjugated framework provides
0
, 2000
. (a) J. Fernández-Ariza, R. M. K. Calderón, M. S. Rodríguez-
periodicity to the catalytic site along with the facile electron Morgade, D. M. Guldi and T. Torres, J. Am. Chem. Soc., 2016,
5
1
Angew. Chem. Int. Ed., 2016, 55, 2425
38, 12963; (b) P. Manna, J. Debgupta, S. Bose and S. K. Das,
transportation. This eventually minimizes the probability of
aggregation of the catalytic centre. Also, the permanent
porosity in the framework helped the diffusion of substrate to
the catalytic sites. The stability of the Co-PC monomer was
6
7
1
.
.
U. H. F. Bunz, Chem. Rev., 2000, 100, 1605
J. Chen, M. A. Reed, A. M. Rawlett and J. M. Tour, Science,
999, 286, 1550
studied by running 100 cycles of LSV. Figure 3f showed the 8. (a) S. Roy, A. Hazra, A. Bandyopadhyay, D. Raut, P. L.
th
Madhuri, D. S. S. Rao, U. Ramamurty, S. K. Pati, S. K. Prasad and
T. K. Maji, J. Phys. Chem. Lett., 2016, , 4086; (b) S. Roy, D.
Samanta, P. Kumar and T. K. Maji, Chem. Commun., 2018, 54
deteriorated activity of Co-PC at 100 cycle which was due to
leaching of cobalt species noticeable under naked eye (Figure
S13). Leaching of cobalt decreases the number of active sites
and hence explains the reduced activity. To ascertain no
7
,
,
2
9
75
.
(a) K. Maeda and K. Domen, J. Phys. Chem. Lett., 2010,
1
leaching of cobalt from CoCMP into the electrolytic solution, 2655; (b) J. Yang, X. Wang, B. Li, L. Ma, L. Shi, Y. Xiong and H. Xu,
Adv. Funct. Mater., 2017, 27, 1606497
0. (a) X. Sun, L. Gao, C. Guo, Y. Zhang, X. Kuang, T. Yan, L. Ji and
Q. Wei, Electrochimica Acta, 2017, DOI:
0.1016/j.electacta.2017.07.091; (b) Y. Surendranath, M. W.
Kanan and D. G. Nocera, J. Am. Chem. Soc., 2010, 132, 16501; (c)
Q. Xiao, Y. Zhang, X. Guo, L. Jing, Z. Yang, Y. Xue, Y.-M. Yan and K.
Sun, Chem. Commun., 2014, 50, 13019.
ICP was recorded both before and after 1000 cycles of LSV.
CoCMP showed no appearance of Co in the electrolytic
solution after 1000 cycles. Therefore, CoCMP exhibited no
leaching of cobalt sites from the framework. This further
proved the necessity of framework.
1
1
2
+
In summary, we have designed new N4 coordinated Co
1
1. (a) N.-T. Suen, S.-F. Hung, Q. Quan, N. Zhang, Y.-J. Xu and H.
M. Chen, Chem. Soc. Rev., 2017, 46, 337; (b) Y. Zhang, T. Gao, Z.
Jin, X. Chen and D. Xiao, J. Mater. Chem. A, 2016, , 15888.
2. S. C. Riha, B. M. Klahr, E. C. Tyo, S. Seifert, S. Vajda, M. J.
containing phthalocyanine based porous conjugated organic
polymer which has potential for catalysing OER. Interestingly,
we observed that the enmeshed mononuclear Co(II) with even
4
1
low loading (1.7 %) in rigid organic framework shows efficient Pellin, T. W. Hamann and A. B. F. Martinson, Acs Nano, 2013,
7,
2
1
396.
3. (a) H. B. Aiyappa, J. Thote, D. B. Shinde, R. Banerjee and S.
electro-catalytic activity. CV and LSV showed an anodic current
onset at 1.57 V with overpotential of 340 mV and Tafel slope
of 87 mV/decade. The consistent catalytic performance of the
CoCMP even after 1000 cycles endorses its excellent stability
Kurungot, Chem. Mater., 2016, 28, 4375; (b) N. Sikdar, B.
Konkena, J. Masa, W. Schuhmann and T. K. Maji, Chem. Eur. J.,
2
017, 23, 1.
without leaching of the metal ions. On the other hand the 14. see suporting information
1
5. J.-M. Lee, J. W. Kim, J. S. Lim, T. J. Kim, S. D. Kim, S.-J. Park
and Y.-S. Lee, Carbon Science, 2007, , 120.
6. S. Aoi, K. Mase, K. Ohkubo and S. Fukuzumi, Chem. Commun.,
015, 51, 10226
7. J. Niklas and O. G. Poluektov, Adv. Energy Mater., 2017, 7,
diminished stability and the leaching of CoPC into the solution
explained the necessity of a framework. The inactivity of
ZnCMP towards OER exhibits the importance of the judicious
selection of metal ion while designing the catalyst.
8
1
2
1
1
1
602226.
8. C. C. L. McCrory, S. Jung, J. C. Peters and T. F. Jaramillo, J.
AS thanks Department of Science & Technology (DST), New
Delhi, India for the National post-doctoral fellowship (DST
project No. PDF/2016/002324). TKM is grateful to the DST
Am. Chem. Soc, 2013, 135, 16977
1
9. X. Lu and C. Zhao, Nat. Comm., 2015, 6, 6616.
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins