Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported onto CO2 Capture Materials

Article abstract of DOI:10.1002/cssc.201702338

Cu is a unique catalyst for CO₂ electroreduction, since it can catalyze CO₂ reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO₂ is considered to facilitate the activity and selectivity of CO₂ reduction. Herein, a new strategy is presented for CO₂ reduction with improved C₂H₄ selectivity on a Cu catalyst by using CO₂ capture materials as the support at ambient pressure. N-doped carbon (N_xC) was synthesized through high-temperature carbonization of melamine and l-lysine. We observed that the CO₂ uptake capacity of N_xC depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600–800 °C). The as-prepared CuO/N_xC catalysts exhibit a considerably higher C₂H₄ faradaic efficiency (36 %) than CuO supported on XC-72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C₂H₄ faradaic efficiency and CO₂ uptake capacity of the supports for CuO. The local high CO₂ concentration near Cu catalysts, created by CO₂ capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C₂H₄. This study demonstrates that pairing Cu catalysts with CO₂ capture supports is a promising approach for designing highly effective CO₂ reduction electrocatalysts.

Full text of DOI:10.1002/cssc.201702338

DOI: 10.1002/cssc.201702338
Full Papers
Promoting Ethylene Selectivity from CO Electroreduction
2
on CuO Supported onto CO Capture Materials
2
[
a]
[a]
[a]
[a]
[a]
Hui-Juan Yang, Hong Yang, Yu-Hao Hong, Peng-Yang Zhang, Tao Wang, Li-
[
a]
[a]
[b]
[a]
[a]
Na Chen, Feng-Yang Zhang, Qi-Hui Wu, Na Tian, Zhi-You Zhou,* and Shi-
[a]
Gang Sun*
Cu is a unique catalyst for CO electroreduction, since it can
zation temperature (600–8008C). The as-prepared CuO/N C cat-
2
x
catalyze CO reduction to a series of hydrocarbons, alcohols,
alysts exhibit a considerably higher C H4 faradaic efficiency
2
2
and carboxylic acids. Nevertheless, such Cu catalysts suffer
(36%) than CuO supported on XC-72 carbon black (19%), or
unsupported CuO (20%). Moreover, there is a good linear rela-
tionship between the C H faradaic efficiency and CO uptake
from poor selectivity. High pressure of CO is considered to fa-
2
cilitate the activity and selectivity of CO reduction. Herein, a
2
2
4
2
new strategy is presented for CO reduction with improved
capacity of the supports for CuO. The local high CO concen-
2
2
C H selectivity on a Cu catalyst by using CO capture materials
tration near Cu catalysts, created by CO2 capture materials,
was proposed to increase the coverage of CO intermediate,
which is favorable for the coupling of two CO units in the for-
mation of C H . This study demonstrates that pairing Cu cata-
2
4
2
as the support at ambient pressure. N-doped carbon (N C) was
x
synthesized through high-temperature carbonization of mela-
mine and l-lysine. We observed that the CO uptake capacity
2
2
4
of N C depends on both the microporous area and the content
lysts with CO capture supports is a promising approach for
x
2
of pyridinic N species, which can be controlled by the carboni-
designing highly effective CO reduction electrocatalysts.
2
Introduction
[
5]
[6]
There are two promising ways to close the anthropogenic CO
creasing catalyst roughness, surface molecular modification,
2
[1]
[7]
cycle: one is to transfer CO into value-added products and
regulating nanostructures, raising local pH near the electrode
2
[
2]
[8]
the other is to capture CO for sequestration. In respect of
surface, and introducing alkali metal cations, halogen anions
2
[6,9]
CO conversion, converting CO into energy-dense fuels and
and organic functional groups,
have also been reported to
2
2
chemical feedstocks has attracted widespread concerns be-
cause it is a scalable solution for environment and energy
increase the production of hydrocarbons by CO reduction. For
2
[6]
example, Xie et al. reported that when Cu nanoparticle surfa-
ces were functionalized with N-containing ligands such as
[
3]
needs. Cu is known to catalyze CO reduction to hydrocar-
2
[
4]
bons in considerable quantities. However, traditional Cu elec-
trodes suffer from low product selectivity to hydrocarbons, as
well as the severe side reaction of hydrogen evolution.
amino acids, hydrocarbon generation by CO reduction can be
2
+
enhanced, owing to the introduction of NH3 groups that can
stabilize the CHO* intermediate through the hydrogen bond
+
To tune the reaction pathways, many researchers have
found that Cu catalysts derived from Cu oxides can enhance
the activity and selectivity to hydrocarbons, particularly ethyl-
ene (C H ), at negative potentials. Other methods, such as in-
between CHO* and NH3 . In addition, boosting the CO pres-
2
sure is also an effective approach. Sakata and co-workers first
reported that increasing the CO pressure drastically improves
2
[10]
the activity of CO reduction. Hori proposed that increasing
2
4
2
the CO pressure not only increases the activity, but also affects
2
[11]
the selectivity of the products, a proposal that was then sup-
[
a] H.-J. Yang, H. Yang, Y.-H. Hong, P.-Y. Zhang, T. Wang, L.-N. Chen,
F.-Y. Zhang, N. Tian, Prof. Z.-Y. Zhou, Prof. S.-G. Sun
State Key Laboratory of Physical Chemistry of Solid Surfaces
Collaborative Innovation Center of Chemistry for Energy Materials
College of Chemistry and Chemical Engineering, Xiamen University
Xiamen 361005 (PR China)
[12]
ported in a study by Chaplin and Wragg. They reported that
the boosting the CO pressure could effectively inhibit the hy-
2
drogen evolution reaction and suggested that the change in
yÀ
selectivity was caused by promoting the generation of a CO
x
[12]
intermediate. For Cu electrodes, increasing CO pressure has
2
E-mail: zhouzy@xmu.edu.cn
been shown to facilitate CO reduction to multi-carbon prod-
sgsun@xmu.edu.cn
2
[13]
ucts. Melchaeva et al. used CO supercritical fluid as an elec-
[b] Q.-H. Wu
2
Department of Materials Chemistry
School of Chemical Engineering and Materials Science
Quanzhou Normal University
trolyte at high pressure and found that the byproducts of CO2
reduction are inhibited effectively and the selectivity to alco-
[14]
hols is increased. Koper et al. have shed light on the influ-
Quanzhou 362000 (China)
ence of increasing CO pressure, and found it significantly en-
2
Supporting information and the ORCID identification number(s) for the
author(s) of this article can be found under https://doi.org/10.1002/
cssc.201702338.
[15]
hances the C H selectivity on Cu catalysts. All of these re-
2
4
sults clearly highlight the great importance of the CO pressure
2
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on CO reduction. However, studies of CO pressure require
2
2
Results and Discussion
specific reactors and external pressures. We consider whether
it is possible to construct a local microenvironment with high
All of the N C samples (N C-6008C, N C-7008C, and N C-8008C)
x
x
x
x
CO pressure/concentration around the catalysts under moder-
were found by scanning electron mictroscopy (SEM) to have
rough and porous structures (Figure 1A–C), which was further
confirmed by transmission electron microscopy (TEM; inset).
The porosity of the carbon matrix increased with increasing
carbonizing temperature. The pore structure will affect the
2
ate pressure.
To this end, CO capture materials may meet such a require-
2
ment. When Cu-based catalysts are supported by CO -capture
2
materials, CO can be adsorbed and potentially form a local mi-
2
[17]
croenvironment with high CO concentration around the cata-
ability of CO adsorption. To further identify the pore struc-
2
2
lysts. To our knowledge, although many studies have con-
cerned the supports of CO2 reduction electrocatalysts, the
strategy of manipulating the activity and selectivity by tuning
ture of these CO capture materials, nitrogen adsorption–de-
2
sorption isotherms of the three samples were tested (Fig-
ure 1D). All samples gave rise to a pseudo-type IV curve with a
H2-type hysteresis loop at high relative pressure, which is a
CO uptake capacity of the supports has not been reported to
2
[18]
date. Among CO capture materials, N-doped carbon materials
typical feature of mesoporous materials. The specific surface
area was calculated by the Brunauer–Emmett–Teller (BET)
2
exhibit excellent performance, owing to their porous structure
[
16]
2
À1
and the properties brought about by N doping.
method. That of N C-6008C was only 208 m g , whereas
x
In this study, we synthesized N-doped carbon materials (N C)
those of N C-7008C and N C-8008C were significantly increased
x
x
x
2
À1
from nitrogen-rich melamine and l-lysine precursors. The CO2
at 478 and 512 m g , respectively. This result indicates that in-
creasing the carbonizing temperature will promote the forma-
tion of a larger surface area. The pore size distribution shows
the main pore size concentrated around 7.4 nm (inset of Fig-
uptake capability of the N C can be controlled by tuning the
x
carbonizing temperature (600, 700, or 8008C). The target cata-
lysts were prepared by loading CuO onto the N C. We found
x
that these catalysts not only enhance the activity of CO reduc-
ure 1D). With regards to CO adsorption capacity, micropores
2
2
[19]
tion, but also tune the selectivity to ethylene, in comparison
are more important than mesopores. The microporous areas
with CuO supported on non-CO -capture materials (e.g., XC-72
of N C-6008C, N C-7008C, and N C-8008C are 33, 126, and
113 m g , respectively.
2
x
x
x
2
À1
carbon black). We also derived a linear correlation of the ethyl-
ene selectivity with the CO adsorption capacity of the sup-
Besides pore structure, the types of doped nitrogen are also
2
ports.
very important for the CO adsorption capacity. The nitrogen
2
species were analyzed by the high-resolution N1s X-ray photo-
electron spectroscopy (XPS; Figure 2A–C). Three peaks were
x x x
Figure 1. A–C) SEM images of the N C-6008C (A), N C-7008C (B), and N C-8008C (C). Insets show TEM images. D) Nitrogen adsorption–desorption isotherms of
the three samples.
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Figure 2. A–C) High-resolution N 1s XPS spectra of N
x
C-6008C (A), N
x
C-7008C (B), and N
x
C-8008C (C). D) CO
2
adsorption isotherms at 298 K.
deconvoluted, corresponding to pyridinic N at 398.5 eV, pyrrol-
cantly. The length of laminar structures ranged from 50 to
100 nm and the dendrite width ranged from 7 to 15 nm. CuO/
N C-6008C and CuO/N C-8008C showed similar morphologies
[
20]
ic N at 399.9 eV, and graphitic N at 401 eV. XPS of the three
samples showed that pyridinic N is the dominant nitrogen spe-
x
x
cies. N C-7008C had the highest proportion of pyridinic N
to CuO/N C-7008C, whereas CuO/XC-72 mainly consisted of a
x
x
(
60.8%), followed by N C-6008C (52.8%) and N C-8008C
48.1%). Increasing the carbonizing temperatures to 8008C in-
mixture of agglomerated particles and laminar structures with
wider dendrites (see the Supporting Information, Figure S1).
XRD measurements were carried out to ascertain the CuO
phase structures (Figure 3C). Most of the diffraction peaks
(35.68, 38.88, 48.68, 66.28, and 67.98) came from monoclinic
CuO (PDF#02-1040). The samples showed almost consistent
patterns, indicating that the crystal structure of CuO is not in-
fluenced by the supports. The total weight contents of Cu in
the samples were measured by energy-dispersive X-ray spec-
x
x
(
creased the content of graphitic N to 23%, whereas N C-7008C
and N C-6008C only have 10 and 18% of graphitic N, respec-
tively. Among three types of nitrogen, pyridinic N has the high-
x
x
[19]
est alkalinity, and is of great importance for CO adsorption.
2
However, in our study, the CO adsorption capacity was not
2
completely consistent with the content of pyridinic N. The CO2
capture capacities at 298 K of different materials (Figure 2D)
À1
followed the order: N C-7008C (2.18 mmolg )>N C-8008C
(
troscopy (EDS) to be 22.5, 22.1, 23.2, and 21.2% for CuO/N C-
x
x
x
À1
À1
1.95 mmolg )>N C-6008C (1.28 mmolg ). Vulcan XC-72
6008C, CuO/N C-7008C, CuO/N C-8008C, and CuO/XC-72, re-
x
x
x
À1
carbon only has a CO uptake capacity of 0.47 mmolg . The
spectively (Table S1). Although the loss of Cu was inevitable
during the preparation process, the Cu contents were similar
in these four samples. To further confirm the CuO surface state
of these samples with different supports, high-resolution Cu2p
2
lower CO capture capacities of N C-6008C in comparison to
N C-8008C may be attributed to the very low microporous
area of the former. This result indicates that both large micro-
porous area and high content of pyridinic N play significant
roles in capturing CO2.
2
x
x
3/2
were collected using XPS (Figure 3D). The Cu2p spectrum
was fitted by three peaks at 932.5, 933.6, and 934.8 eV. The rel-
0
+
Figure 3A shows the TEM image of CuO without carbon
support. It adopts a laminar structure with some dendrites
about 70 nm in length. Figure 3B depicts the TEM image of
atively weak peak at 932.5 eV represents Cu and Cu , and the
2
+ [21]
other two peaks are associated with Cu
.
The presence of
0
+
Cu and Cu peaks implies that Cu was not completely oxi-
2
+
2+
CuO/N C-7008C. The dispersity of CuO was improved signifi-
dized to Cu . Cu is the dominant form in all samples, which
x
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Figure 3. TEM images of unsupported CuO (A) and CuO/N
008C, N C-7008C, N C-8008C, and XC-72 carbon black.
x
x
C-7008C (B). XRD pattern (C) and high-resolution XPS of Cu2p3/2 (D) of CuO supported on N C-
6
x
x
[12]
is in accordance with the XRD results. Note that most of the
Wragg reported. In contrast, Vulcan XC-72 has a low CO2
capture capacity and hydrogen evolution is a significant side
reaction under negative potentials (Figure S4).
CuO will be reduced to metallic Cu under the CO electrore-
2
duction conditions.
Figure 4A shows the steady-state polarization curves of CO2
The main gaseous products of the CO reduction are CO,
2
reduction on CuO/N C-7008C, CuO/XC-72, and unsupported
C H , and CH . In addition, there are trace liquid products (such
x
2
4
4
CuO in CO -saturated 0.1m NaHCO3 solution (pH 6.8). The
as formic acid, ethanol, and propanol), and the total FEs of
liquid products is less than 10% (Figure S5). As the potential
shifts negatively, the FE for CO decreases, whereas those for
C H and CH increase (Figure 4B–D). This indicates that the in-
2
steady-state total current was recorded at 2000 s when the
contribution of CuO reduction to the total current can be ne-
glected and the faradaic efficiencies (FEs) of gaseous products
also reach stable values (Figure S2). The current was normal-
2
4
4
termediate adsorbed *CO can be further reduced to hydrocar-
[22]
ized by the Cu mass on the electrode surface. CuO/N C-7008C
bon at a negative potential. CuO/N C-7008C has a considera-
x
x
and CuO/XC-72 have total current densities about two times
bly higher C H4 selectivity than CuO and CuO/XC-72 at all
2
that of unsupported CuO. The FEs for H are 60% on CuO/XC-
tested potential ranges. The highest FE value for C H is 36%,
2
2
4
7
2, 40% on CuO, and 30% on CuO/N C-7008C (Figure 4B–D).
obtained on CuO/N C-7008C at À1.25 V, whereas the FE values
x
x
Considering the variety of CO reduction products, the neat
on CuO and CuO/XC-72 are only 20 and 19%, respectively. This
2
CO reduction current was calculated by subtracting the hydro-
result indicates that using a CO capture material as the sup-
2
2
gen evolution partial current from the total current. The neat
port benefits the formation of C H .
2
4
CO reduction currents for different catalysts follows the order
To further explore the influence of CO capture materials,
2
2
CuO<CuO/XC-72<CuO/N C-6008CꢀCuO/N C-8008C<CuO/
the FEs for products on CuO/N C-6008C and CuO/N C-8008C
were also obtained (Figure 5). The FE values for C H follow
2 4
x
x
x
x
N C-7008C (Figure S3). Such a difference may result from the
x
support effects. As a CO capture material, N C-7008C could
the order CuO/N C-7008C>CuO/N C-8008C>CuO/N C-6008C.
x x x
2
x
adsorb CO to form a local microenvironment with high CO2
In previous studies, the presence of pyridinic N was considered
an important factor in promoting C H4 formation by CO re-
2
concentration, which leads to the promotion of CO reduction
2
2
2
23]
[
and the suppression of hydrogen evolution, as Chaplin and
duction on Cu catalysts supported on N-doped carbon. In
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Figure 4. A) Mass-normalized total current densities of CO
rated 0.1m NaHCO solution (pH 6.8). B–D) FEs of gaseous products for CO
violet), CH (red), and C (black); GC sampling was performed at 2000 s during potentiostatic electrolysis.
2
reduction on unsupported CuO, CuO/N
x
2
C-7008C, and CuO/XC-72 at various potentials in CO -satu-
3
2 x 2
reduction on CuO (B), CuO/XC-72 (C), and CuO/N C-7008C (D). H (orange), CO
(
4
2 4
H
2 x x
Figure 5. Product FEs of CO reduction on CuO/N C-6008C (A) and CuO/N C-8008C (B) at different potentials.
this study, this is not the case. In fact, N C-6008C has higher
Although the carbon supports contained trace Fe, Ni, Zn, and
Co (Table S2), as detected by inductively coupled plasma mass
spectrometry (ICP-MS), they have very poor catalytic activity
for CO reduction. The FE for H was almost 100% (Figure S6)
x
content of pyridinic N than N C-8008C, whereas the FE values
x
for C H at À1.15 V are 25% on CuO/N C-6008C and 30% on
2
4
x
CuO/N C-8008C. Therefore, other factors besides the concen-
x
2
2
tration of pyridinic N species must greatly influence the C H4
with trace CO. 2) The electrical conductivity of carbon supports
2
selectivity.
can also be excluded. The electrical conductivity of the N C in-
x
We can exclude some factors from carbon supports. 1) First-
ly, the influence of trace metals in the supports can excluded.
creased with increasing carbonization temperature from 600 to
8008C, and XC-72 exhibited the highest value (Figure S7 and
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Table S3). This order of conductivity is significantly different
from that of C H selectivity observed on different carbon sup-
our study, CO capture materials (e.g., N C-7008C) can maintain
2
x
a local environment with high CO concentration, and facilitate
2
4
2
ports. 3) The support electronic effects are also not the main
mass transfer. This may help to increase the *CO coverage on
the Cu catalyst surface, and further facilitate the coupling of
two CO molecules to form C H .
reason for the observed dependence of C H4 selectivity on
2
carbon supports. In principle, carbon supports, especially N-
doped carbon, may influence the oxidation state of the metal
supported on them through metal–support interactions and
thus change the reaction kinetics. However, such support ef-
fects will decrease with increasing size of metal nanoparticles.
2
4
Conclusions
[
23]
For example, Li et al. reported that the pyridinic N species in
N-doped graphene have little effect on Cu nanoparticles larger
We synthesized N-doped carbon materials with different CO2
uptake capacities for use as supports for CuO electrocatalysts.
than 13 nm for CO reduction. In our study, CuO had particle
The target CO -reduction catalyst, CuO loaded onto N-doped
2
2
sizes ranging from 50 to 100 nm. For such large particles, the
electronic effect from the supports is little. In fact, we observed
no shift in the binding energy of Cu2p in the XPS obtained
from different CuO supported samples (Figure 3d). 4) The Cu
loading is the same essentially for four carbon-supported CuO
carbon, exhibits much higher C H selectivity than CuO loaded
2
4
onto common carbon black, as well as unsupported CuO. We
found a good linear relationship between C H selectivity and
2
4
CO uptake capacity of the carbon supports, which may guide
2
the preparation of CO -reduction catalysts with high C H se-
2
2
4
catalysts. And the morphology and size of CuO for three C N-
lectivity. Further studies are needed to characterize the oxida-
tion state of Cu catalysts in operando and to reveal the de-
tailed mechanism for boosting C H selectivity by CO -capture
x
supported samples are also similar. So that, the catalyst load-
ing, morphology, and size (or surface area) are unlikely to
govern the different C H selectivity.
2
4
2
2
4
supports.
Finally, we found that the CO uptake capacity of the sup-
2
ports correlates well with the C H selectivity. Figure 6A shows
2
4
the potential dependence of C H selectivity for four CuO cata-
2
4
Experimental Section
lysts supported on different carbon supports. To reduce the
measurement errors, the tests were repeated three times at
each potential. The plot of C H selectivity against CO uptake
Synthesis of N-doped carbon materials
2
4
2
The N-doped carbon materials were prepared by a pyrolysis
method. Melamine (2.0 g), l-lysine (1.0 g) and SBA-15 mesoporous
silica (0.4 g) were mixed together with deionized water (5 mL) and
ethanol (5 mL), and were ultrasonically dispersed for 0.5 h to form
capacity at P/P =1 is shown in Figure 6B. Clearly, a good
0
linear relationship between the FE for C H and the capacity of
2
4
CO uptake can be observed for all four tested potentials. Con-
2
[27]
sidering CO reduction was carried out in CO -saturated 0.1m
a uniform suspension, then dried at 908C to form a powder. The
2
2
NaHCO solution, we further tested the CO adsorption capaci-
powder was carbonized in two steps by heating under an Ar at-
3
2
mosphere in a tube furnace at 3008C for 1 h with a heating rate of
ties in this solution for above carbon supports (Figure S8 and
Table S4). The order of adsorption capacities tested in the solu-
À1
3
7
8Cmin , and then heating up to elevated temperature (6008C,
008C, and 8008C) for 2 h at 58Cmin . The SBA-15 template was
À1
tion is consistent with that obtained by CO gas adsorption.
2
then removed by using a 20% HF solution. After centrifugation
and washing with deionized water (about 20 mL) several times, as
well as drying, the N-doped carbon materials were obtained, and
referred as N C-6008C, N C-7008C, and N C-8008C for those ob-
It has been generally accepted that the formation of C H is
2
4
mainly through dimerization of two adsorbed *CO intermedi-
[
24,25]
ates during CO reduction on Cu.
Therefore, the high cov-
2
x
x
x
[26]
erage of *CO should be in favor of the formation of C H . In
tained at the corresponding carbonized temperature.
2
4
Figure 6. A) FEs of C
for C and the CO
2
H
4
for CO
2
reduction on CuO catalysts supported on four carbon supports at different potentials. B) Linear relationship between the FE
2
H
4
2
uptake capacity on carbon supports at P/P
0
=1 and room temperature.
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Synthesis of CuO supported on N-doped carbon materials
CuO catalysts supported on N-doped carbon materials (CuO/N C)
x
Acknowledgements
were prepared through a reduction and re-oxidation approach.
Firstly, CuCl ·2H O (60 mg) and N C (50 mg) were dispersed in de-
2
2
x
The study was financially supported by the National Key Research
and Development Program of China (2017YFA0206500), the Na-
tional Science Foundation of China (21573183, 91645121, and
ionized water (20 mL) in a 100 mL flask, followed by the addition
of 0.5m NaOH solution to afford a neutral system. NaBH (25 mg)
4
was then dissolved in water (20 mL) and the solution was added
2
+
21621091), the Natural Science Foundation of Fujian Province
slowly to the mixture and then kept stirring for 4 h, whereby Cu
was reduced into metallic Cu nanoparticles. The samples were col-
lected by filtering and washed with deionized water (about 30 mL).
Finally, the sample underwent heat treatment at 2008C for 3 h in
air to afford the CuO/N C-6008C, CuO/N C-7008C, or CuO/N C-
(2016J01069), and “Tong-Jiang Scholar” programs. We thank
Prof. Qiu-Quan Wang, Yang Zhou,and Ying Guo for the trace
metal test, and Dong Li for the electrical conductivity test.
x
x
x
8
008C catalysts. For comparison, we also prepared CuO supported
on Vulcan XC-72 carbon black (CuO/XC-72) by a similar procedure. Conflict of interest
In comparison with the N C, XC-72 carbon black has a low CO ad-
x
2
sorption capacity. In addition, CuO without carbon support was
also prepared.
The authors declare no conflict of interest.
Keywords: carbon capture
· CO2 reduction · copper ·
electrocatalysis · support effects
[
[
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À2
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[
[
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2
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ChemSusChem 2018, 11, 1 – 9
www.chemsuschem.org
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ꢀ 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
These are not the final page numbers! ÞÞ

Full Papers
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Manuscript received: January 26, 2018
Revised manuscript received: January 15, 2018
Version of record online: && &&, 0000
[
1
&
ChemSusChem 2018, 11, 1 – 9
www.chemsuschem.org
8
ꢀ 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

FULL PAPERS
The higher the better: CuO supported
H.-J. Yang, H. Yang, Y.-H. Hong,
P.-Y. Zhang, T. Wang, L.-N. Chen,
F.-Y. Zhang, Q.-H. Wu, N. Tian,
Z.-Y. Zhou,* S.-G. Sun*
on N-doped carbon, a CO capture ma-
2
terial, exhibits high faradaic efficiency
for CO electroreduction. The higher
2
CO uptake capacity, the higher C H se-
2
2
4
&& – &&
lectivity. The local high CO concentra-
2
tion near the Cu catalysts, created by
Promoting Ethylene Selectivity from
the CO capture materials, is proposed
CO Electroreduction on CuO
2
2
to increase the coverage of CO inter-
mediate, which is favorable for the cou-
pling of two CO units in the formation
of C H .
Supported onto CO Capture Materials
2
2
4
ChemSusChem 2018, 11, 1 – 9
www.chemsuschem.org
9
ꢀ 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
These are not the final page numbers! ÞÞ