In situ generated highly active copper oxide catalysts for the oxygen evolution reaction at low overpotential in alkaline solutions

Article abstract of DOI:10.1039/c6cc00526h

Developing efficient water oxidation catalysts made up of earth-abundant elements has attracted much attention as a step toward for future clean energy production. Herein we report a simple one-step method to generate a low cost copper oxide catalyst film in situ from a copper(ii) ethylenediamine complex. The resulting catalyst has excellent activity toward the oxygen evolution reaction in alkaline solutions. A catalytic current density of 1.0 mA cm^-2 and 10 mA cm^-2 for the catalyst film requires the overpotentials of only ～370 mV and ～475 mV in 1.0 M KOH, respectively. This catalytic performance shows that the new catalyst is one of the best Cu-based heterogeneous OER catalysts to date.

Full text of DOI:10.1039/c6cc00526h

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In Situ Generated Highly Active Copper Oxide Catalyst for Oxygen
Evolution Reaction at Low Overpotential in Alkaline Solutions
Received 00th January 20xx,
Accepted 00th January 20xx
Xiang Liu, Shengsheng Cui, Manman Qian, Zijun Sun, Pingwu Du*
DOI: 10.1039/x0xx00000x
www.rsc.org/
17-20
Developing efficient water oxidation catalysts made of earth- extensive redox properties.
Thus, Cu-based catalysts have great
potential in energy applications.
Recently, our group reported that heterogeneous copper oxide is
abundant elements has attracted much attention as a step toward
for future clean energy production. Herein we report a simple
one-step method to generate a low cost copper oxide catalyst film
in situ from copper(II) ethylenediamine complex. The resulting
catalyst has excellent activity toward oxygen evolution reaction in
2
1
active for water oxidation, and that the catalytic activities of the
heterogeneous Cu-based catalysts can be tuned by the
22
morphologies and sizes in CuO nanomaterials. We later found that
Cu(OH)
2
is one of the active species for water oxidation during
2
alkaline solutions. A catalytic current density of 1.0 mA/cm and
23
electrodeposition. In addition, a few other groups also reported
that CuO or Cu-Bi is an active catalyst for OER catalysis.
Although much progress has been achieved to explore the Cu-based
2
2
4-25
1
0 mA/cm for the catalyst film requires the overpotentials of only
370 mV and ~475 mV in 1.0 M KOH, respectively. This catalytic
~
performance shows that the new catalyst is one of the best Cu- catalytic systems for OER (Table 1), all of the above-mentioned
based heterogeneous OER catalysts to date.
catalysts still showed lower catalytic activities than cobalt- or nickel-
based catalysts such as mesoporous Co (overpotential, η ~410
3
O
4
2
26
2 10
Conversion of electricity or solar energy into chemical fuels via mV for 10 mA/cm ) , Co-Pi (η ~410 mV for 1.0 mA/cm ), , Co NPs
2
27
2 28
water splitting is a great challenge and the design of highly efficient (η ~390 mV for 10 mA/cm ) , Ni-Bi (η ~430 mV for 1.0 mA/cm ) ,
2
29
and low cost catalysts for oxygen evolution reaction (OER) has and Ni P (η ~400 mV for 10 mA/cm ), . Therefore, it is highly
2
1
-3
attracted great attention. OER catalysis is a four-electron transfer desirable to search for efficient Cu-based catalysts with highly
process coupled with the removal of four protons from water improved performance, which are comparable to the well-known
molecules, which is much more complicated and difficult than cobalt- or nickel-based catalysts for OER.
water reduction reaction for hydrogen (H
2
) production. Therefore,
an efficient OER half-reaction might be the key to achieve high-
4
-6
2
performance water splitting for H production. This point has led
to a high demand for highly active materials for OER catalysis.
Inspired by nature, many catalysts with structure and/or function
similar to Mn cluster have been designed to realize water oxidation
under moderate overpotentials, including well-known Ru- and Ir-
7
-8
based catalysts. More recently, much attention has been focused
on low-cost catalysts based on first-row transition metals such as
5
, 9
2, 10-11
12
13-15
manganese, cobalt (Co),
iron (Fe).
nickel (Ni), copper (Cu),
and
1
6
Figure 1. (a) Molecular structures of the Cu-EA, Cu-PA, and Cu-BA complexes. (b)
Cu is a very attractive element for catalysis because of its high Catalytic current densities for bulk electrolysis at 0.8 V (vs. Ag/AgCl) in 0.1 M KOH
solution containing 3.0 mM Cu-EA (black), Cu-PA (red), and Cu-BA (blue) using
FTO as the working electrode at pH 13.0.
abundance and low cost, which is even cheaper than Co and Ni. In
addition, Cu plays a key role as the active metal center in a series of
enzymes, such as copper monooxygenases, cytochrome C oxidases
II
I
0
and other enzymes. The reduction of Cu to Cu /Cu and oxidation
In this present study, we demonstrate that a heterogeneous Cu-
III
II
to Cu provides Cu with well-defined coordination chemistry and based catalyst that is highly active in alkaline solutions can be
generated in situ from simple copper(II) ethylenediamine (Cu-EA)
and copper(II) 1,3-propanediamine (Cu-PA) complexes (Figure 1a).
In addition, the catalyst exhibited excellent robustness for catalytic
oxygen evolution in 1.0 M KOH and the required overpotentials are
only ~370 mv and ~475 mV to achieve a current density of 1.0
2
2
mA/cm and 10 mA/cm , respectively. These overpotentials for
water oxidation, to the best of our knowledge, are better than all
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the reported Cu-based heterogeneous catalysts for water oxidation. the catalytic performance was much worse than either of the other
The catalyst material was extensively studied by scanning electron complexes (blue plot in Figure 1b). No obvious catalytic film could
2
microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and be seen and the current density remained as low as 0.1 mA/cm for
powder X-ray diffraction (XRD).
2
3 hours. Obvious blue Cu(OH) precipitate was observed at the
bottom of the electrochemical cell, indicating that Cu-BA complex is
not stable in such a strong alkaline solution and the complex
decomposed to form Cu(OH) . Therefore, among these three
2
Initially, three copper complexes Cu-EA, Cu-PA, and Cu-BA were
used as the catalysts for water oxidation catalysis. Bulk electrolysis
BE) experiments using a bare FTO electrode as the working
(
copper complexes, only Cu-EA and Cu-PA can be used as good
precursors to generate active copper-based heterogeneous catalyst
in 0.1 M KOH for water oxidation. Since the Cu-EA complex
precursor showed the better catalytic activity, it was then chosen
for the subsequent catalytic studies.
electrode were performed in a 0.1 M KOH solution (pH ~13)
containing 3.0 mM different copper complexes. A Pt wire was used
as the counting electrode and an Ag/AgCl (3 M KCl) electrode was
utilized as the reference electrode. As shown in Figure 1b, the
catalytic current density in Cu-EA solution rapidly increased under
an applied potential of 0.8 V vs. Ag/AgCl in the first hour. A large
To provide more insights into the heterogeneous catalyst
amount of gas bubbles appeared on the surface of the electrode. generated in situ from Cu-EA solution, the material was
The gas was confirmed to be oxygen by both gas chromatography characterized by powder X-ray diffraction (XRD), as shown in Figure
and a fluorescence-based oxygen sensor, indicating that water 2a. The diffraction patterns of the material on the FTO electrode
oxidation catalysis had occurred in this conditions. After long-term were sharp and can be ascribed to typical CuO diffraction character
2
electrolysis for 3 h, the catalytic current density impressively (PDF#89-5895) and the SnO character on the FTO substrate
2
reached ~10 mA/cm and a black-gray thin film was clearly (PDF#46-1088). No other impurity peak can be observed. These
observed on the FTO electrode (see the inset picture in Figure 1b), results indicate high crystallinity and good purity of the
suggesting the Cu-EA complex probably served as the active catalyst electrodeposited CuO catalyst materials. The main crystalline peaks
precursor for water oxidation.
of the catalyst were located at the (-111) and (111) phases.
Table 1. Copper-based heterogeneous catalysts for OER
Figure 2. (a) Powder XRD patterns, (b) high resolution XPS spectrum of Cu 2p, (c)
SEM image, and (d) high resolution TEM image of electrodeposited CuO material
obtained from Cu-EA. Inset: the cross-sectional SEM image of the catalyst thin
film on FTO plate.
The chemical compositions and the valence states of the catalyst
film were further examined by XPS (Figure 2b and Figure S2). The
XPS survey spectrum reveals that the deposited materials mainly
contain Cu, O, and C elements (Figure S2a) and the C 1s peak (285.0
eV) was used as the reference. The valence states of Cu and O
elements were further probed by high-resolution XPS spectra of Cu
Continuous cyclic voltammogram (CV) scans using 3.0 mM Cu-EA
complex in 0.1 M KOH showed consistent results with increasing
catalytic current density (Figure S1), further confirming the
formation of heterogeneous active catalyst on the FTO electrode. In
Figure S1, the initial CV scan between 0 and 0.8 V vs. Ag/AgCl at a
scan rate of 100 mV shows obvious catalytic potential after ~0.6 V.
With continuous CV scans for 1000 cycles, the catalytic onset
potentials for water oxidation significantly decreased from ~0.6 V to
2
p, Cu LMM, and O 1s. In the Cu 2p spectra (Figure 2b), obvious
shake-up satellite peaks suggested that the oxidation state of Cu
2
1-22
element is probably +2.
2
Since both CuO and Cu(OH) materials
have similar Cu 2p3/2 character, it is necessary to further confirm
2
+
the real source of Cu by examining the Cu LMM spectrum. In the
Cu LMM spectrum (Figure S2b), an obvious single peak located at
9
CuO.
18.2 eV is observed, which is consistent with the fingerprint of
2
2-23, 30
The high-resolution O 1s spectrum was also collected
~0.5 V vs. Ag/AgCl. Meanwhile, the catalytic current density was
(
Figure S2c) and the result further confirmed the +2 valence state of
highly enhanced. For example, the corresponding value increased
2
2
the electrodeposited Cu-based catalyst. One peak at 529.4 eV was
probably from the oxygen element in CuO and another two peaks
located at 530.8 eV and 532.3 eV are tentatively assigned to the
from 0.8 mA/cm to 5.7 mA/cm at 0.8 V. As before, a black thin
film was observed on the FTO during continuous CV scans and
obvious oxygen gas bubbles were generated.
chemisorbed hydroxyl oxygen and chemisorbed water molecules, as
When using the Cu-PA complex to replace Cu-EA in solution to
perform the BE experiment under the same conditions (red plot in
Figure 1b), similar black-gray thin film was generated during
electrodeposition, while a lower current density of 8.5 mA/cm was
achieved after 3 hours for electrolysis. When using Cu-BA complex,
23, 30
also reported in previous studies.
Therefore, the
electrodeposited catalysts from Cu-EA precursor were identified as
CuO materials. Grey film electrodeposited from Cu-PA precursor
2
was also examined by XRD and XPS and the results are shown
in
2
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Figure S3, which exhibited nearly the same chemical compositions 1.0 M KOH (Figure 3b). The results show that the catalytic
as the material obtained from Cu-EA precursor.
overpotentials under different current densities exhibited no
significant increase for 10 hours, suggesting good stability of the
catalyst for OER catalysis. Consistent with the LSV results, the
Figure 2c shows the SEM images of the electrodeposited CuO
materials from Cu-EA complex on FTO after 3 hours of electrolysis.
The CuO materials contains interlaced nanoblocks with a length of
2
overpotentials for 1.0 and 10 mA/cm were located at only ~370 mV
and ~475 mV, respectively. Large amounts of gas bubbles were
observed on the surface of the electrode, as seen in the inset
picture in Figure 3b and the movie S1 for oxygen evolution provided
in SI). In addition, the Tafel plot was obtained by measuring LSV at a
scan rate of 2 mV/s in 1.0 M KOH (Figure 4a). The slope obtained
from the plot is ~90 mV/dec for catalytic current densities from 1.0
~
500 nm. It is worth mentioning that the surfaces of these
nanoblocks are full of noticeable cracks which may help increase
the surface area. The inset image in Figure 2c is the cross-section of
the film, illustrating its thickness of ~780 nm after 3 hours of
electrolysis. The morphology of electrodeposited CuO materials
from Cu-PA was also provided in Figure S4. It is found that the
material electrodeposited from Cu-PA has similar thickness to the
materials obtained from Cu-EA precursor but shows more irregular
nanostructure. Figure 2d shows a high-resolution TEM image of the
CuO material obtained from Cu-EA, in which the phase distance
between the adjacent lattice fringes is 0.252 nm, corresponding to
the (-111) crystal plane of the standard CuO diffraction pattern (PDF
2
2
mA/cm to 10 mA/cm .
#89-5895).
To further investigate the catalytic activities of the catalyst film
for OER, linear sweep voltammograms (LSV) were performed in 1.0
M KOH solution (pH ~13.6) at a scan rate of 10 mV/s using the
electrodeposited CuO film (electrodeposition at 0.8 V vs. Ag/AgCl
for 3 h) from Cu-EA precursor as the working electrode. The black
plot in Figure 3a is the control experiment using a bare FTO
electrode and the red plot shows the LSV data of CuO film with no
iR compensation. No obvious catalytic activity was observed from
the control experiment at 1.2 V to 1.8 V vs. RHE. In contrast, the as-
electrodeposited CuO film showed excellent catalytic activity for
oxygen evolution in water. The overpotential to generate 10
2
mA/cm for the present CuO film is only ~470 mV (1.70 V vs. RHE).
To the best of our knowledge, this catalytic performance is much
higher than other copper-based heterogeneous catalysts for water
Figure 3. (a) Polarization curves for the CuO material electrodeposited from Cu-
EA with 20% iR compensation (blue) and without iR compensation (red) in 1.0 M
1
3, 21-25, 31
oxidation, as shown in Table 1.
These results confirm that KOH buffer solution at pH 13.6. (b) Catalytic overpotential plots using the active
2
the electrodeposited CuO material is an active catalyst for water CuO material under static current densities of 1.0 and 10 mA/cm for 10 hours in
1
.0 M KOH solution. Inset: oxygen bubbles on the surface of the CuO/FTO
oxidation. Moreover, the influence of the iR compensation was
studied and the LSV data obtained with 20% iR compensation are
shown in Figure 3a (blue plot). When 20% iR compensation was
applied, the curve for OER was much sharper than the catalytic plot
electrode.
The Faradaic efficiency was calculated based on the catalytic
2
without iR compensation and much higher catalytic current performance of the CuO thin film catalyst at 1.0 mA/cm in a gas-
densities were obtained under the same applied potential. For tight electrochemical cell in 1.0 M KOH. The amount of evolved O2
2
example, to achieve a current density of 10 mA/cm , the applied during OER over a certain period of electrolysis was measured by a
working potential was ~1.65 V vs. RHE, which is less than the ~1.70 fluorescence-based oxygen sensor. The experiment was performed
V (red plot) with no iR compensation.
for 4 hours and the corresponding plots are shown in Figure 4b.
Oxygen was observed rapidly after initiating electrolysis and the
amount of oxygen rose with the increase of passed charge. The
theoretical yield of oxygen is calculated by assuming that all of the
current was caused by 4e oxidation of water to produce oxygen.
Comparing the experimental data with the theoretical data, the
amount of oxygen evolved corresponds to a Faradaic yield which is >
The LSVs of the CuO films obtained from Cu-PA and Cu-EA
precursors in 1.0 M KOH solution are compared in Figure S5. The
results showed the CuO film deposited from Cu-EA has much better
catalytic activity for OER than that obtained from Cu-PA. The
roughness factor (RF) may explain the different OER performances
in two CuO films, which was realized by measuring the CVs at
various scan rates in the non-Faradaic region (Figure S6). Based on
the results, Cdl of the CuO film from Cu-EA showed a much higher
-
9
5%.
value than that from Cu-PA (RF=Cdl/(C
electrochemical double layer capacitance and
s
*Sgeo),
C
dl is the
C
s
is specific
electrochemical double layer capacitance of an atomically smooth
surface). The higher value of Cdl in the CuO film from Cu-EA
indicated a higher RF and further resulted in a higher performance
toward OER. As the CuO material deposited from Cu-EA showed a
better catalytic property, the following experiments are focused on
this CuO film.
Figure 4. (a) The Tafel plot and (b) Faradic efficiency of oxygen production using
the CuO thin film catalyst electrodeposited from Cu-EA in 1.0 M KOH solution.
The catalytic stability of the as-deposited CuO material for OER
was measured in galvanostatic electrolysis at 1.0 and 10 mA/cm in
2
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1
0 M. W. Kanan, D. G. Nocera, Science, 2008, 321, 1072-1075.
After electrolysis for 10 hours, the surface composition and 11 V. Artero, M. Chavarot-Kerlidou, M. Fontecave, Angew.
valence states of the CuO catalyst film material was probed again by Chem. Int. Ed., 2011, 50, 7238-7266.
XPS experiments. Figure S7a shows the Cu 2p spectra of the 12 M. Dincă, Y. Surendranath, D. G. Nocera, Proc. Natl. Acad. Sci.
catalyst. Compared to the freshly electrodeposited CuO material,
very similar shake-up satellite peaks and Cu 2p3/2 peaks were
observed for the catalyst after OER catalysis and these peaks are
U.S.A., 2010, 107, 10337-10341.
1
4
1
7
3 S. M. Barnett, K. I. Goldberg, J. M. Mayer, Nat. Chem., 2012,
, 498-502.
2
+
21, 23, 30
consistent with the typical character of Cu in CuO.
In
4 Z. F. Chen, T. J. Meyer, Angew. Chem. Int. Ed., 2013, 52, 700-
addition, the Cu LMM spectrum showed an obvious single peak
located at 918.2 eV and further confirmed the durability of the CuO
03.
2
2-23, 30
15 M. T. Zhang, Z. F. Chen, P. Kang, T. J. Meyer, J. Am. Chem.
Soc., 2013, 135, 2048-2051.
(
Figure S7b).
electrolysis showed nearly the same diffraction peaks as the fresh
sample (PDF# 89-5895) and SnO on FTO substrate (SnO PDF# 77-
452) (Figure S7c). Therefore, after electrolysis, there still exists Chem. Soc., 2010, 132, 10990-10991.
XRD results for the CuO material after
1
6 W. C. Ellis, N. D. McDaniel, S. Bernhard, T. J. Collins, J. Am.
2
2
0
only pure CuO on the FTO electrode. Based on the above- 17 M. Taki, S. Itoh, S. Fukuzumi, J. Am. Chem. Soc., 2001, 123
,
mentioned XRD and XPS results, the present in situ generated CuO 6203-6204.
material is quite robust for OER catalysis.
1
1
1
6
8 L. M. Mirica, O. X, T. D. P. Stack, Chem. Rev., 2004, 104, 1013-
045.
9 C. J. Cramer, W. B. Tolman, Acc. Chem. Res., 2007, 40, 601-
Conclusions
08.
In summary, our present study reports a simple one-step method 20 P. Kang, E. Bobyr, J. Dustman, K. O. Hodgson, B. Hedman, E. I.
to form highly active heterogeneous CuO catalyst in situ from Cu-EA
complex for OER catalysis in alkaline conditions. The OER activity of
the CuO catalyst showed a very low overpotential of only ~470 mV
Solomon, T. D. P. Stack, Inorg. Chem., 2010, 49, 11030-11038.
1 X. Liu, H. Jia, Z. Sun, H. Chen, P. Xu, P. Du, Electrochem.
Commun., 2014, 46, 1-4.
2
2
to achieve 10 mA/cm in 1.0 M KOH at pH 13.6. This performance
2
2
2
1
2
2 X. Liu, S. Cui, Z. Sun, P. Du, Electrochim. Acta, 2015, 160, 202-
makes it one of the most efficient known copper-based
heterogeneous catalyst for water oxidation. Furthermore, the
electrodeposited CuO material is quite robust during water
oxidation, as evidenced by XRD and XPS measurements after a long
period of electrolysis. The simple synthesis method, low cost, and
08.
3 X. Liu, H. Zheng, Z. Sun, A. Han, P. Du, ACS Catal., 2015, 5,
530-1538.
4 F. Yu, F. Li, B. Zhang, H. Li, L. Sun, ACS Catal., 2014, 5, 627-
high activity of the present CuO thin film catalyst highlight its great 630.
potential as an efficient catalyst for future low-cost electrochemical 25 T. T. Li, S. Cao, C. Yang, Y. Chen, X. J. Lv, W. F. Fu, Inorg.
water splitting devices.
Chem., 2015, 54, 3061-3067.
This work was financially supported by NSFC (21271166, 26 Y. J. Sa, K. Kwon, J. Y. Cheon, F. Kleitz, S. H. Joo, J. Mater.
1473170), the Fundamental Research Funds for the Central Chem. A, 2013, , 9992-10001.
Universities, the Program for New Century Excellent Talents in 27 L. Wu, Q. Li, C. H. Wu, H. Zhu, A. Mendoza-Garcia, B. Shen, J.
2
1
University (NCET), and the Thousand Young Talents Program.
Guo, S. Sun, J. Am. Chem. Soc., 2015, 137, 7071-7074.
8 M. Dinca, Y. Surendranath, D. G. Nocera, Proc. Natl. Acad. Sci.
U.S.A., 2010, 107, 10337-10341.
2
Notes and references
2
5
3
9 A. Han, H. L. Chen, Z. J. Sun, J. Xu, P. Du, Chem. Comm., 2015,
, 11626-11629.
0 N. S. McIntyre, S. Sunder, D. W. Shoesmith, F. W. Stanchell, J.
1
1
J. L. Dempsey, B. S. Brunschwig, J. R. Winkler, H. B. Gray, Acc.
Chem. Res., 2009, 42, 1995-2004.
Vac. Sci. Technol., 1981, 18, 714-721.
1 J. L. Du, Z. F. Chen, S. R. Ye, B. J. Wiley, T. J. Meyer, Angew.
2
3
1
4
5
4
6
4
7
P. Du, R. Eisenberg, Energy Environ. Sci., 2012, 5, 6012-6021.
3
N. S. Lewis, D. G. Nocera, Proc. Natl. Acad. Sci. U.S.A., 2006,
03, 15729-15735.
Chem. Int. Ed., 2015, 54, 2073-2078.
D. G. Nocera, Acc. Chem. Res., 2012, 45, 767-776.
J. P. McEvoy, G. W. Brudvig, Chem. Rev., 2006, 106, 4455-
483.
Table of contents
R. Tagore, R. H. Crabtree, G. W. Brudvig, Inorg. Chem., 2008,
7
, 1815-1823.
J. J. Concepcion, J. W. Jurss, M. K. Brennaman, P. G. Hoertz, A.
O. T. Patrocinio, N. Y. M. Iha, J. L. Templeton, T. J. Meyer, Acc.
Chem. Res., 2009, 42, 1954-1965.
8
1
9
D. Gust, T. A. Moore, A. L. Moore, Acc. Chem. Res., 2009, 42,
890-1898.
G. C. Dismukes, R. Brimblecombe, G. A. N. Felton, R. S.
Pryadun, J. E. Sheats, L. Spiccia, G. F. Swiegers, Acc. Chem. Res.,
2
009, 42, 1935-1943.
4
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