Chitosan coated copper-oxide nano particles: A novel electro-catalyst for CO2 reduction

Article abstract of DOI:10.1039/c4ra12696c

We report here a simple one-pot method for the synthesis of copper-oxide based novel film forming electro catalysts for CO₂ reduction. Water dispersible chitosan (CS)-CuO/Cu₂O (Cu_xO) nano composites of diameter 10-20 nm were obtained by hydrothermal reactions of CS, CuSO₄·5H₂O and tartaric acid (TA). Here, TA acts as a multifunctional reagent as de-polymerizer of CS, ionic cross linker of depolymerised CS and complex forming ligand with Cu²⁺ ions. These CS coated Cu_xO nanoparticles were characterized by HRTEM, UV-VIS, AFM, FTIR and XPS. An ultra thin film of composite catalyst was deposited onto a Pt electrode by drop cast techniques and applied to study CO₂ reduction by cyclic voltammetric techniques. The voltammogram shows a reduction peak at -0.665 V vs. RHE at pH 5.3 with a short hydrogen evolution tail indicating its better performance in terms of retarding the H₂ evolution reaction. This has been explained proposing a model of protonated CS on the electrode surface that repels incoming H⁺ ions at the electrode-electrolyte interface. This is the first time a film forming copper-oxide based nano composite material for efficient electro-catalytic reduction of CO₂ in aqueous solution has been reported.

Full text of DOI:10.1039/c4ra12696c

View Article Online
View Journal
RSC Advances
This article can be cited before page numbers have been issued, to do this please use: S. Basumallick
and S. Santra, RSC Adv., 2014, DOI: 10.1039/C4RA12696C.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
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. This Accepted Manuscript will be replaced by the edited,
formatted and paginated article as soon as this is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
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 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.
www.rsc.org/advances

Page 1 of 6
RSC Advances
View Article Online
DOI: 10.1039/C4RA12696C
RSC Advances
RSCPublishing
COMMUNICATION
Cite this: DOI:
Chitosan coated copper-oxides nano particles: A novel
1
0.1039/x0xx00000x
electro-catalyst for CO reduction
2
a,b,c
b,c
Srijita. Basumallick
and Swadeshmukul.Santra
Received 00th January 2012,
Accepted 00th January 2012
DOI: 10.1039/x0xx00000x
www.rsc.org/
1
1
We report here a simple one-pot method of synthesis of carbon pathway is not capable of restoring the ecological CO
2
balance because of rapidly increasing global carbon emission. Thus,
CO2 utilization through its photoꢀchemical or electroꢀchemical
is an additional effective path in restoring CO balance.
But major bottleneck of CO reduction reaction is that it is an uphill
copper–oxide based novel film forming electro catalyst for
CO reduction. Water dispersible chitosan (CS)-CuO/Cu O
2
2
1ꢀ10
reduction
2
(
Cu O) nano composites of diameter 10-20 nm was obtained
x
2
by hydrothermal reactions of CS, CuSO .5H O and tartaric
4
2
reaction and kinetically difficult because of requirement of high
1
1
acid (TA). Here, TA acts as a multifunctional reagent as de- activation energy. In natural photosynthetic dark reaction free
polymerizer of CS, ionic cross linker of depolymerised CS energy of cleavage of phosphate bond of ATP and reducing
2
+
molecule NADPH are used to fix and reduce CO to carbohydrate.
The enzyme Ribulose Bisphosphate Carboxylase (RuBPCO) acts as
catalyst. In laboratory experiments with CO reduction using sun
light or electrical energy, it is known oxides of copper; particularly
and complex forming ligand with Cu ions. These CS coated
2
Cu O nanoparticles were characterized by HRTEM, UV-VIS,
AFM, FTIR and XPS. An ultra thin film of composite catalyst
was deposited onto a Pt electrode by drop cast technique and
x
2
5ꢀ7
Cu O is an efficient catalyst for such reduction. This is because of its
2
applied to study CO2 reduction by cyclic voltametric unique crystalline structures1
0,12
where CO2 molecules get easily
technique. The voltammogram shows a reduction peak at - adsorbed with favourable heat of adsorption.
In this paper, we intend to focus on chitosan coated nano Cu O
0
.665 V vs. RHE at pH 5.3 with a short hydrogen evolution
x
composite catalyst for CO reduction; we have selected chitosan as it
2
tail indicating its better performance in terms of retarding H2
evolution reaction. This has been explained proposing a
model of protonated CS on to electrode surface that repels
13
has the ability to form an ultra thin adhesive film onto electrode
surface that will reduce catalyst loading. Chitosan loaded composite
14
electrode has been successfully applied in immobilizing enzyme
+
incoming H ion at the electrode-electrolyte interface. This is
for bioꢀfuel cells. Film forming ability of chitosan with linear chain
13
the first time we are reporting a film forming copper-oxide structure has been studied using solidꢀstate NMR and Xꢀray
diffraction techniques. These studies have revealed that H bonding
ability of chitosan along with its strong cross linking ability through
based nano composite material for efficient electro-catalytic
reduction of CO in aqueous solution.
2
its protonated –NH groups with polyꢀvalent anion of a cross linker
2
makes it an unique film forming material.
Introduction
12
DFT calculations on CO reduction onto Cu based catalysts
2
1ꢀ10
revealed different mechanistic paths for such reduction. These
During the recent years, there is an increasing interest
in the
12
calculations have shown possible mechanistic path for multi
development of photoꢀcatalysts and electroꢀcatalysts for CO2
reduction. Carbon dioxide is a greenhouse gas and a major
contributor of global warming. Natural photosynthetic pathway or
electron transfer reactions involve in CO reduction.
2
15
Recently, Flake et al reported Cu nano cluster loaded ZnO
electrode for CO2 reduction and shown that different reduction
products as methane, CO, ethylene, methanol, ethanol, methyl
_
____________________________________________________________
a
Department of Chemistry, National Institute of Technology, Agartala,
Tripura 799046, India,
5ꢀ7
formate are formed as reduction products. Hori et al have shown
CH is the major product of Cu O electrode surface. Again, it is
b
c
NanoScience Technology Center and Department of Chemistry, University
4
2
15
of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826.
E-mail: srijitabasumallick@gmail.com
reported CO reduction occurs within the potential range ꢀ0.6 to ꢀ
2
1
.4 V vs. Ag/AgCl or ꢀ0.065 V to ꢀ0.865 V vs RHE at pH 5.3. Usoki
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 1

RSC Advances
Page 2 of 6
View Article Online
COMMUNICATION
DOI: 10.1039/C4RA1269
RSC Advan6Cces
1
6
and his group showed that at low over potential CO reduction
CS solution (1%w/v) in 1% (v/v) HCl was heated at 150ºC for
90 min. The pH of the solution was raised to 7.4 by adding 1.0 N
2
leads to formation of formic acid.
1
0
Ogura et al in their review article discussed the mechanism of NaOH drop wise to this depolymerized CS solution. The final
ethylene formation and pointed out that CO is adsorbed onto Cu solution was centrifuged and reꢀdispersed in DI water. The washing
2
electrode prior to electro reduction.
procedure was continued for 3 to 4 times. The solution was vortexed
In this paper, we report a simple oneꢀpot hydrothermal method for 15 minutes between each centrifuge and washing step. The solid
of synthesis of chitosan coated nano copper–oxide catalyst and palate was vacuum dried for FTꢀIR analysis.
studied their electroꢀcatalytic activity towards CO2 reduction.
Chitosan is an excellent film forming material, it is anticipated CS
Characterization
coated Cu O nano composite will be a promising catalytic material
x
UltravioletꢀVisible Spectroscopy (UVꢀVIS): UVꢀVIS absorption
spectra of the prepared catalysts and their controls have been taken
in the range 200–800 nm using Varian Cary 300 Bio UVꢀVis double
beam spectrophotometer in a semi micro quartz cuvette with path
length 10 mm.
for efficient electroꢀreduction of CO . To the best of our knowledge
this has not been reported earlier.
2
Experimental
Fourier Transform Infraꢀred Spectroscopy (FTꢀIR): FTꢀIR
technique was used to characterize functional groups present in these
four samples. FTꢀIR spectra were recorded on Perkin Elmer
Spectrum 100 ATR FTꢀIR Spectrometer.
TEM Images: FEI Tecnai TEM with resolution 0.20 nm point to
point, 0.102 nm per line was used. The machine was equipped with
SEG with hot and cold stages and High angle annular dark field
Materials
Water insoluble low molecular weight Chitosan was purchased
from Sigma Aldrich (Saint Louis, Missouri, USA) and used
without further treatment. CuSO .5H O, (technical grade) was
purchased from CQ concepts INC (Ringwood, Illinois, USA).
NaOH (ACS grade, Amresco Solon, Ohio, USA) and HCl
4
2
(HAADF) detector using Gatan Image Filter (GIF). The lyophilized
(
technical grade, Fisher Scientific.) were used as supplied.
catalyst powder was dispersed in ethanol. Au grid with carbon mass
was directly dipped in to the solution and after absorption was dried
under vacuum for 24 hr to remove any solvent.
AFM Images: Water dispersed sample was spin coated and dried
in vacuum onto a silicon wafer (boron doped, purchased from Nova
electronic materials). AFM images were recorded on a Veeco
Manifold multimode V model (tapping mode) using silicon nitride
tip (radius B 50 nm) attached to a cantilever (spring constant=0.032
Nm, oscillating frequency 0ꢀ600 kHz). AFM images were recorded
at room temperature.
Hydrothermal reaction was carried out in a hard glass well
stopper bomb keeping in a temperature controlled oven
(
Thermo electron corporation, Lundeberg/Blue M). A Mettler
Toledo, Delta 320 pH meter was used to adjust pH of the
solution after calibrating it using HACH pH calibration
solutions. Barnsted Nano pure Diamond DI water was used to
obtain DI water of resistivity 17.9 MΩcm. Fisher scientific
Digital vortex mixers was used to mix reagents for reaction.
Preparation of chitosan coated copper-oxides nano particles
by hydrothermal method.
XPS images: XꢀRay Photoelectron Spectroscopy (XPS) was
done on a Physical Electronics 5400 ESCA spectrometer equipped
In this preparation of CS coated Cu O, we had optimised with a monochromatic Al Ka source operating at 300 W. Vision
x
the reaction conditions for obtaining almost water dispersible software provided by the manufacturer was used for data analysis
(
fewer agglomerated particles) product. Here, we took 300 mg and quantification. A Shirley background was used for quantification
of chitosan and 300 mg of tartaric acid that acts as and curve fitting of Cu2p, C1s, N1s and O1s spectra. All the spectra
depolymerizer, ionic cross linker and complex forming agent, were charge referenced to the aliphatic carbon at 285 eV. For curveꢀ
in a hydrothermal bomb to that 30 ml of DI water was added, fits, 70% Gaussian/30% Lorentzian line shape was used.
mixed well and kept at 150ºC under hydrothermal condition for
1
Fabrication of CuꢀCS composite and control Cu O loaded
2
.5 hours. After the reaction was over, the solution was cooled electrodes for CV studies: Catalyst loaded electrodes were prepared
to room temperature and 25 ml of (1% w/v) CuSO solution by conventional drop cast method. 100 uL of dispersed CuꢀCS was
4
2
was added to the hydrothermally depolymerized solution and added to a 1 cm cleaned Pt electrode and the water was evaporated
kept under vortex for one hour followed by addition of 1.0 N under vacuum. Similar procedure was followed to prepare control
NaOH drop wise to adjust its pH to 7.4. Then, 5 ml of this electrode. For cyclic voltammetry study, the catalyst loaded
solution was added to 25 ml DI water and kept under electrode was used as working electrode coupled with a Pt counter
hydrothermal at 150ºC for one hour to convert remaining electrode and Ag/AgCl reference electrode. The electrodes were
Cu(OH) completely to Cu O/CuO. The final dispersed solution dipped into a solution taken in a beaker containing 10 ml of 0.1 M
2
2
was dialysed centrifuged and dried under vacuum for further Na
studies.
SO
measurement by reaction of 2 ml 0.2 M Na
H SO . CV was recorded at a scan rate of 200 mVs in the potential
solution saturated with CO
, prepared just before the
2
4
2
CO and 2 ml 0.2 M
2
3
ꢀ
1
2
4
window of +0.8 to ꢀ2.0 V, the CV diagrams are shown in Fig. 6ꢀ
.The potential values are plotted in RHE at pH 5.3 for the sake of
Preparation of control CuO/Cu O (without CS)
2
7
1
7
We followed literature protocol of preparation of copperꢀoxide comparison with literature data
nano, dissolving 300 mg of Cuꢀacetate (in 30 ml of 10% CH COOH
3
solution followed by hydrothermal reaction at 150ºC for 90 min and
pH of the solution was adjusted to 7.4. This dispersion was dialysed
Results and Discussions
against DI water, centrifuged and dried under vacuum. It was
proposed that Cuꢀacetate undergoes disproportionation reaction nanoparticles and their control. A flat absorption peak around 450
under hydrothermal condition forming Cu and CuO.
Fig. 1 shows UVꢀvisible spectra of CS coated copperꢀoxide
nm with minima around 250 nm is seen. This featureless absorption
behaviour may be due to presence of both Cu (I) and Cu (II) oxides
in the composites. It is interesting to note that the UV spectra of the
Preparation of control CS solution.
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 3 of 6
Journal Name
RSC Advances
View Article Online
COMMUNICATION
DOI: 10.1039/C4RA12696C
control NPs show a sharp absorption peak at 250 nm. This may be
attributable to the presence of uncoated Cu (I) oxide in the control.
Fig. 1 UVꢀVis spectra of CSꢀCu O composite and control.
x
IR spectra of these catalysts and their control are shown in Fig 2.
1
8
These are more or less similar to the reported spectra CS
ꢀ
1
coordinated copper complex. The broad peak around 3400 cm of
CS due to –OH and –NH stretching is reduced substantially in the
2
CS coated catalyst due to its low concentration onto NM surface.
ꢀ
1
However, presence of –CH stretching at 2900 cm in the spectra of
catalyst clearly indicate that copper oxides NMs are capped with CS.
ꢀ
1
Appearance of a carbonyl peak at around 1659 cm and amide (II)
ꢀ
1
18
1
503 cm (blue shifted
because of capping) as well as
ꢀ
1
characteristic amide (III) at 1356 cm , reinforces presence of CS,
ꢀ
1
ꢀ1
together with this 1255 cm , 1022 cm , for glycosidic bond also
indicates presence of chitosan. A pictorial representation of the CS
coated nano material is shown in Fig 3. It is seen that depolymerized
CS will easily bind to metalꢀoxide nanoparticles by ligand binding
mode and will be dispersible in aqueous medium because of presence
of hydrophilic groups.
Fig. 3 Schematic representation of chitosan coated CuO/Cu O
nano particles
x
AFM images of this catalyst and its control are shown in Fig. 4.
It is seen that distinct non agglomerated particles of relatively
smaller sizes are formed with catalyst in contrast to catalyst control
where particles are mostly agglomerated. AFM image shows these
NMs are composed of particles of different sizes as expected from
their preparation method.
Fig. 2 FTIR spectra of CSꢀCu O and its control.
x
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 3

RSC Advances
Page 4 of 6
View Article Online
COMMUNICATION
DOI: 10.1039/C4RA1269
RSC Advan6Cces
Fig. 4 AFM images of CSꢀCu O (top left) (particle diameter
x
Fig. 6a CV of CO reduction on to Pt| CSꢀCu O at a scan rate of 200
2 x
mVs .
ꢀ
1
~
400 nm), thickness of the catalyst film (~18 nm, bottom) and
AFM image of the control (top right).
Electroꢀcatalytic activities of these CSꢀCu oxides catalysts
XPS images of CSꢀCuO/Cu O indicate presence of mixed
valence states Cu (II) and Cu (I) on the surface. While Cu (I) state is
x
towards CO reduction have been studied by cyclovoltammetry (CV)
2
techniques. Cyclovoltamograms of CO2 reduction using these
catalyst loaded electrodes in 0.1 M Na SO solution saturated with
predominating in CSꢀCuO/Cu O catalyst, Cu (II) oxide is present at
x
2
4
ꢀ
1
a larger percentage on the surface of the control sample (Fig. 4). This
may be owing to reducing property of CS. The peak at 932 eV and
auger parameter 1848 eV is due to Cu 2p3/2 and characteristic of Cu
I) state. In survey spectra the peak for N 1s indicates presence of
CS. Different functional groups present in chitosan help in coating
formation as seen in C 1s as well as O 1s peaks.
HRTEM analysis shows (Fig. S1) formation of nanoparticles of
core diameter 10ꢀ15 nm with d spacing of 4.2 Å (characteristic of
Cu O, 111), these crystals also show presence of grain bounderies.
CO (pH=5.3) at scan rate of 200 mVs are shown in Fig. 6ꢀ7, scan
2
ꢀ
1
rate is optimised at 200 mVs to obtain significant peak current
values and minimize Cu (II) formation during forward scan. A
typical CV for this system using control catalyst at a scan rate of 50
(
ꢀ
1
mVs is shown in Fig. S2. Interestingly, the current values are
reduced almost 10 folds compare to those at higher scan rate (Fig.
7
); as a result, some important reduction peak like peak at ꢀ0.24 vs
RHE of Fig.7 become almost invisible. The appearance of initial
small reduction peaks at around 0.535 V and 0.085 V vs RHE at pH
2
Pt crystal with grain bounderies shows higher current density in I/V
curve, we anticipate similar behaviour with our catalyst material.
5
.3 (Fig.6) are owing to the reduction of Cu (II) to Cu and Cu (II) to
Cu (I) respectively. These values are close to the reported values of
1
2
1
9
Theoritical calculations on CO adsorption onto Cu O crystal show
2
2
these redox couples on to Cu powder pasted on graphite electrodes.
most favourable adsorption occurs on 111 plane of Cu O crystal.
2
From SAED analysis, we find brighest ring due to 111 planes
indicating these nano crystals will adsorb CO easily. The chitosan
2
film embedded Cu O catalyst are seen in low magnification (Fig.S1).
2
Fig. 6b CV of CO reduction onto Pt|CSꢀCu O at scan rate of 200
mVs .
2
x
Fig. 5 XPS of CSꢀCu O (top, left) and Cu O, control (bottom),
x
x
ꢀ1
survey scan of CSꢀCu O (top, right).
x
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 5 of 6
Journal Name
RSC Advances
View Article Online
COMMUNICATION
DOI: 10.1039/C4RA12696C
Cyclovoltamograms of CO2 reduction using different electroꢀ
2
0
catalysts including Cu O, CuꢀZnO composite have been reported
2
2
0
earlier that shows a long downward cathodic tail due to H2
evaluation reaction (HER) along with a small CO reduction peak.
2
2
0
We have also observed similar cathodic tail owing to H evaluation
2
reaction (HER) with our Cu O control without CS (Fig. 7).
2
ꢀ
1
Fig. 7 CV of CO reductions onto Pt/Cu O at a scan rate 200 mVs .
2
x
But with CS composites of Cu O, this tail appears (Fig.6) after ꢀ
x
0
.865 V with a small peak at ꢀ0.665 V vs RHE at pH 5.3 attributable
to CO reduction. This indicates HER onto CSꢀCu oxides composite
2
Fig. 8 Schematic diagram showing positively charged barrier
formation of CS coated Cu O catalyst that retards H evolution
reaction.
surface is retarded probably due to protonation of free amino groups
+
x
2
of CS which repels incoming H towards electrode surface as shown
in Fig. 8. It is interesting to note that basic features of the clyclo
voltammogram remains unaltered after repeating the cycles and
changing the scanning directions which indicate that the catalysts are
21
15(a)
not poisoned by the reduction products. Carpenter et al reported
that an indole based amine acts as a good photo catalyst for reduction onto CuꢀZnO surface holding potential at ꢀ1.4 V vs
Flake et al
has reported good Faradic efficiency for CO2
15(b)
conversion of CO to formic acid.
Ag/AgCl and in another paper
this group has pointed out that
2
thinner copperꢀoxide layers are found to improve efficiency of CO
2
10
electroꢀreduction to methanol. Ogura et al pointed out that CO2
reduction starts at ꢀ0.6 V vs Ag/AgCl and formation of hydroꢀ
carbons like ethelene, methane etc occur at ꢀ1.2 V vs Ag/AgCl. It is
well reported that CO reduction potential, onset and cathodic peak
2
1
5(b)
potential dependent on the reaction conditions
like pH of the
2
2
solution, composition and morphology of the catalyst as these
factors mainly dictate the reaction path and products of the reactions.
Generally, mixtures of different products as CO, HCOOH, CH OH,
3
5,6,10,15
CH , CH =CH etc are formed
during such electro reduction
4
2
2
process owing to multi steps electroꢀchemical (EC) and chemical
11
15
mechanistic paths. It is reported CH OH is the major reduction
3
product onto Cu O surface though it involves six electron transfer
2
reaction.
ꢄ
ꢅ
CO ꢁgꢂ ꢃ 6H ꢃ 6e ꢆ CH OHꢁaqꢂ ꢃ H Oꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇ
ꢀ
ꢀ
ꢀ
ꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇꢇE ꢆ ꢃ0.02ꢇVꢇvsꢇSHE
ꢈ
From Fig. 6, it is seen that CO reduction starts at ꢀ0.075 V vs
2
RHE at pH 5.3 or + 0.025 V vs SHE with a peak potential at ꢀ0.665
V vs RHE, indicating possible formation of mixture of products
including methanol as the observed potential is close to the reported
value of oxidation potential of methanol onto Cu O surface. We
2
have repeated the experiment several times using freshly prepared
CSꢀCu oxides catalyst and successively using the catalyst coated
This journal is © The Royal Society of Chemistry 2012
J. Name., 2012, 00, 1-3 | 5

RSC Advances
Page 6 of 6
View Article Online
COMMUNICATION
DOI: 10.1039/C4RA1269
RSC Advan6Cces
electrodes, we got an excellent reproducible results indicating 17 M. Yin, C. Wu, Y. Lou, C. Burda, J. T. Koberstein, Y. Zhu and
stability of the CS coated catalyst and its control. Here, we have not S. Brien, J. Am. Chem. soc., 2005, 127, 9506.
found any signature of methanol oxidation peak at the anodic scan; 18 J. Kang, H. Liu, Y. M. Zheng, J. Qua and J. P. Chen, J. Colloid.
this may be due to extremely low methanol concentration on the
Interf. Sci., 2010, 344, 117.
electrode surface. Methanol formation as a major product of CO
19 M. Jayalakshmi and K. Balasubramanian, Int. J. Electrochem.
Sci., 2008, 3, 1277.
2
1
1,15
reduction onto Cu O surface is well reported.
and augments our
2
analysis on onset potential of CV experiment
20 M. Le, M. Ren, Z. Zhang, P. T. Sprunger, R. L. Kurtz and J. C.
Flakea, J. Electrochem. Soc., 2011, 158 (5), 45.
In aqueous environment the H evolution reaction cannot be
2
23
eliminated. H so formed may undergo dissociative adsorption onto 21 D. Robert, E. Richardson, J. Holland and B. Carpenter, Nat.
catalytic surface promoting chemical reduction path. In our control
2
1
1
Chem., 2011, 3, 301.
experiment with Cu O prepared using literature protocol, we found a 22 J. L. Qiao, P. Jiang, J. S. yuiouLiu and J. J. Zhang, Electrochem.
x
small peak at ꢀ0.24 V vs RHE that is because of electroꢀreduction of
Commun., 2014, 38, 8.
23 C. W. Li, J. Ciston and M. W. Kanan, Nature., 2014, 508, 504.
1
0
adsorbed CO in a different path as suggested by Ogura.
2
Conclusions
Notes
In this communication, we have prescribed a simple method of oneꢀ Acknowledgement: Author is thankful to Matthew Mcinnis of NSTC, UCF for
pot synthesis of 10ꢀ20 nm sizes CS coated CuO/Cu O nano electroꢀ his help and suggestions on CV experiment.
2
catalyst for CO reduction. We have demonstrated for the first time
2
that CSꢀCu O nano composite is an ultra thin film forming electroꢀ
x
catalyst for CO reduction in aqueous media and it retards hydrogen
2
evolution reaction. This suggests CSꢀCuO/Cu O is a new thin film
2
forming composite electroꢀcatalyst for efficient CO reduction.
2
References
1
C. Costentin, M. Robert and J. M. Save´ant, Chem. Soc. Rev.,
013, 42, 2423
2
2
3
H. Takeda and O. Ishitani, Coord. Chem. Rev., 2010, 254, 346.
D. Windle and R. N. Perutz, Coord. Chem. Rev., 2012, 256,
2
562.
J. A. Keith and E. A. Carter, J. Am. Chem. Soc., 2012, 134,
580.
4
7
5
6
Y. Hori, K. Kikuchi and S. Suzuki, Chem. Lett., 1985, 1695.
Y. Hori, K. Kikuchi, A. Murata and S. Suzuki, Chem. Lett.,
1
986, 897.
7
8
Y. Hori, in Modern Aspects of Electrochemistry, ed. C. G.
Vayenas, R. E. White and M. E. GamboaꢀAldeco, Springer, New
York., 2008, 42, 89.
Z. Xiong, M. Zheng, S. Liu, L. Ma and W. Shen,
Nanotechnology., 2013, 24, 265402.
9
D. Liu, Y. Fernández, O. Ola , S. Mackintosh, M. Maroto, V.
Christopher, M.A. Parlett, A. F. Lee and J. C. S. Wu, Catal.
Commun., 2012, 25, 78.
1
1
0 K. Ogura, Journal of CO Utilization., 2013, 1, 43.
2
1 A. M. Appel, J. E. Bercaw, A. B. Bocarsly, H. Dobbek, D. L.
DuBois, M. Dupuis, J. G. Ferry, E. Fujita, R. Hille, P. J. A.
Kenis, C. A. Kerfeld, R. H. Morris, C. H. F. Peden, A. R. Portis,
S. W. Ragsdale, T. B. Rauchfuss, J. N. H. Reek, L. C. Seefeldt,
R. K. Thauer and G. L. Waldrop, Chem. Rev., 2013, 113(8),
6
621.
1
1
1
1
2 A. A. Peterson, F. AbildꢀPedersen, F. Studt, J. Rossmeisl and J.
K. Norskov, Energy Environ. Sci., 2010, 3, 1311.
3 C. Gartner, B. López, L. Sierra, R. Graf, H. Spiess and M.
Gaborieau, Biomacromolecules., 2011, 12 (4), 1380.
4 C. Kuo1, W. Huang, C. Lee, Y. Liu, C. Chang, H. Yang, and C.
Shieh, Int. J. Electrochem. Sci., 2013, 8, 9242.
5 (a) E. Andrews, M. Ren, F. Wang, Z. Zhang, P. Sprunger, R.
Kurtz and J. Flake, J. Electrochem. Soc., 2013, 160 (11), 841;
(b) M. Le, M. Ren, Z. Zhang, P. T. Sprunger, R. L. Kurtz, and J.
C. Flake, J. Electrochem. Soc., 2011, 158 (5), 45.
1
6 Y. Sun, T. Masuda, and K. Uosaki, Chem. Lett., 2012, 41(3),
3
28.
6
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012