According to the previous studies, water adsorption energy on the metal surface like as Cu strongly dependent
to the structure surface and the size. During the study of the mechanism of the interaction of water
and Cu in water gas shift reaction (WGSR) (CO + H2O CO2 + H2), it has been determined Cu is active
site of catalysis. These studies inspired the authors to consider theoretically the effect of the structure
in the process of the water adsorption in order to select the suitable structures of the copper clusters, Cu10,
for H2 releasing in the fuel cells at B3LYP/6-31G level of theory. The results showed the distinct effect of
the structure on the type of adsorption process (physical or chemical) through three structure of Cu10 (I, II,
III structures, Fig. 1). The structures I and II showed physical surface adsorption in reaction with water
and the structure III showed chemical adsorption with H2 releasing. The adsorption energies are 0.38 ,1.15
,-28.27 (kcal/mol) and ΔGads are 11.14, 13.49, -20.12 (kcal/mol), respectively.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3513

Farzi, N.

Oftadeh, M.

Totonkooban, M.

According to the previous studies, water adsorption energy on the metal surface like as Cu strongly de-pendent to the structure surface and the size. During the study of the mechanism of the interaction of wa-ter and Cu in water gas shift reaction (WGSR) (CO + H2O CO2 + H2), it has been determined Cu is ac-tive site of catalysis. These studies inspired the authors to consider theoretically the effect of the structure in the process of the water adsorption in order to select the suitable structures of the copper clusters, Cu10, for H2 releasing in the fuel cells at B3LYP/6-31G level of theory. The results showed the distinct effect of the structure on the type of adsorption process (physical or chemical) through three structure of Cu10 (I, II, III structures, Fig. 1). The structures I and II showed physical surface adsorption in reaction with water and the structure III showed chemical adsorption with H2 releasing. The adsorption energies are 0.38,1.15,-28.27 (kcal/mol) and ∆Gads are 11.14, 13.49,-20.12 (kcal/mol), respectively

M. Totonkoban

M. Oftadeh

N. Farzi

CiteSeerX

Study of the Structure Effect on Water Adsorption by a Group of Nano Copper Clusters

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 1 No 3, 03PCSI03(3pp) (2012)   2304-1862/2012/1(3)03PCSI03(3) 03PCSI03-1  2012 Sumy State University Study of the Structure Effect on Water Adsorption by a Group of Nano Copper Clusters  M. Totonkoban1, M. Oftadeh1, *, N. Farzi2  1 Chemistry Department, Payame Noor University, 19395-4697 Tehran, I. R. of IRAN 2 Chemistry Department, University of Isfahan, Isfahan, I. R. of IRAN  (Received 4 June 2012; published online 18 August 2012)  According to the previous studies, water adsorption energy on the metal surface like as Cu strongly de-pendent to the structure surface and the size. During the study of the mechanism of the interaction of wa-ter and Cu in water gas shift reaction (WGSR) (CO + H2O  CO2 + H2), it has been determined Cu is ac-tive site of catalysis. These studies inspired the authors to consider theoretically the effect of the structure in the process of the water adsorption in order to select the suitable structures of the copper clusters, Cu10, for H2 releasing in the fuel cells at B3LYP/6-31G level of theory. The results showed the distinct effect of the structure on the type of adsorption process (physical or chemical) through three structure of Cu10 (I, II, III structures, Fig. 1). The structures I and II showed physical surface adsorption in reaction with water and the structure III showed chemical adsorption with H2 releasing. The adsorption energies are 0.38 ,1.15 ,-28.27 (kcal/mol) and ∆Gads are 11.14, 13.49, -20.12 (kcal/mol), respectively.   Keywords: Copper cluster, Watre adsorbtion, Density functional theory, Surface interaction.    PACS numbers: 34.35.+a, 34.50.Lf                                                             * M_oftadeh@pnu.ac.ir 1. INTRODUCTION   Copper is an important transition metal with high electrical and thermal conductivity which is used in many industrial processes in the pure state as sheets, tubes, rods and wires but also as an alloy with other metals. In fact copper is an important material for structural, electrical, and electronics application [1, 2]. Studies show that copper clusters have three dimen-sional interconnected structures quite different from solid state materials. They are aggregates of nanoscale size that have strange physical, chemical, structural, electronical and thermodynamical properties. Duo to broad application of metal clusters in biology, catalysis and nanotechnology, investigation about clusters is an important aspect of theoretical and experimental re-searches. In metal clusters, bridge and hollow positions are important adsorption sides [3]. Analysis of transi-tion metals complexes is critical due to specific molecu-lar properties for systems including high amount of electrons and also for  study the role of ligand–metal interaction in catalystic processes [4]. The water gas shift reaction is wellknown reaction done by heteroge-neous Cu-based catalysts that has important effect in H2 production for fuel cells. In this reaction Cu is active site of catalysis so comprehensive data about water adsorption on Cu surface is useful for understanding the WGSR mechanism [5, 6]. Previous studies confirms that Cu(110) is the borderline between intact and dis-sociative water adsorption and this result could be po-tentially useful in H2 production and its application in fuel cells [7]. These studies also confirm that adsorption energy show strong dependence on the surface struc-ture and the cluster size [8].  Water adsorption is outcome of transition of high amount of charge from water to metal. In fact molecule-metal interaction is arising from electron  donation from the ligand to the metal and  back-donation of electrons the metal to the ligand that these interaction are different for various ligands and weak interaction of M-H2O is electrostatic interaction arising from the penetration of the water dipole into the metal atom charge cloud [4, 9].In this paper only the process of  monomer water adsorption is studied. About the orientation of interaction generally it has been assumed that H2O absorbs "up right" with the O end down and OH bonds pointing away from the sur-face, since this orientation maximizes the adsorbate dipole substrate image-dipole interactions [10].  DFT method is common quantum computation method that energy and other molecular properties in ground state are accessible by applying electron proba-bility density in ground state uniquely. B3LYP method is the most common function including local and non-local terms. DFT analysis should not be done by basis sets lower than 6-31G. DFT methods for transition metals compounds like copper clusters are more relia-ble than HF analysis [11]. In this paper we present the results of quantum mechanical studies about water adsorption process on a group of decade copper clusters, Cu10. This paper pre-sents the results of Cu-H2O interaction in three Cu10 cluster with different structures by density functional method. Special directionality and water adsorption interaction energy is studied too. According to the Conference policy, the proceedings will be published instead of the abstract book. The con-ference proceedings will be published up to the confer-ence sessions for the convenience of the participants and the best dissemination through the Web, since the proceedings paper will be freely available on-line. In order to speed up the availability of your paper online, the submitted manuscript must appear like ready for publication. So, the strict requirements to the manu-script preparation exist.     M. TOTONKOBAN, M. OFTADEH, N. FARZI PROC. NAP 1, 03PCSI03 (2012)   03PCSI03-2 2. THEORETICAL METHODS AND MODELS   2.1 Methods  Different methods and basis set have been tested for Cu + (H2O)n clusters, that results with MP2 and medium sized basis set were in a good agreement with higher level methods like CCSD(T) [2]. B3LYP method and split valence 6-31G and diffuse 6  31 + G* basis sets were selected for optimization copper clusters and H2O. Duo to Cu is a heavy metal B3LYP/GEN was used for analyzing adsorption process. All of calculations were performed by Gaussian 09 Windows that is very powerful program thought the rate of analysis increased 4 times rather than Gaussian 03.  2.2 Models  The most studied cleavage planes for copper are (100) (111) (110). These planes have difficult properties atomic spacing and the adsorption energies will there-fore be different. A surface atom on the (111) plane has nine coordinated atoms, six beside and three below, whereas a surface atom on the (100) plane has eight neighbors, four beside and four below. In fact (111) sur-face has a 3-fold hollow site, whereas the (100) surface has a 4-fold site [6].  Three structures of Cu10 (I, II, and III, Fig. 2)were se-lected and made interaction with water in which the structures  I and II the oxygen took on-top site (upper of one copper atom), and in the structure III the oxygen located in bridge position, upper side of connection site of two Cu atoms.A template is a tool for enforcing a stand-ard layout and look and feel across multiple pages or within content regions. It provides stricter standardiza-tion controls of the documents. In other words, a tem-plate is a form, or pattern used as a guide to making something. Due to it you do not need every time set the margins, spacing, page layout, fonts, format options, etc.   3. RESULTS AND DISCUSSION   Fig. 1 shows water adsorption process on every Cu10 clusters. The results of the calculated electronic energy, EHF, the interaction energy of water with three structures, Eint, the BSSE corrected interaction energy, Eint - BSSE, the Gibbs free adsorbtion energy, ΔGads, at 298 K and 1 atm, the distance of the oxygen atom form Cu, dCu-O, and the HOH angle, < HOH, after adsorbtion have been listed in Table 1.  The results indicate that the water adsorbtion on the structures I and II are physical adsorbtion and the spon-taneous and chemical adsorbtion process occur for the structure III. In this case, water located between two Cu atoms as a bridge with releasing two hydrogen atoms and this could be a suitable model to use in fuel cells. The en-ergy scan diagram versus Cu-O distance for the structures I, II and III have been depicted in Fig. 3.  4. CONCLUSION  In this study B3LYP method and 6-31G basis set was used for optimization of every cluster. Also B3LYP method and 6 – 31 + G* Basis set is used for water op-timization. The studies show that BSSE correction has strong effect on interaction energies. The structure type has direct effect on type of adsorption process. All of the structures achieved positive frequency after optimiza-tion. The results showed physical adsorption in water interaction for the structures I and II, and the other undergo spontaneous chemical adsorption associating H2 releasing. Water orientation and HOH angle change during adsorption process, and it is determined that H2O molecule get close to clusters due to the oxygen atom. The equilibrium distance and energies are report-ed by single point test performance. The oxygen atom of water molecule located in bridge site between two Cu atoms of cluster and released two hydrogen atom in the cluster undergoing chemical adsorption.  Table 1 – Results of the optimization of different structures of Cu10 and of water adsorption on different structures of Cu10  < HOH After ad-sorption d Cu-OoA ∆Gads kcal/mol EHFBSSE kcal/mol Eads kcal/mol EHF Hartree Structure 108.74 1.994 11.14 13.87 0.38 -16402.9410 I 104.91 2.049 13.49 15.91 1.15 -16402.9501 II - - -20.12 30.10 -28.27 -16402.9706 III       III II I Fig. 1 – Water adsorption on Cu10 clusters    I II III Fig. 2 – Selected structures of Cu10   STUDY OF THE STRUCTURE EFFECT ON WATER ADSORPTION… PROC. NAP 1, 03PCSI03 (2012)   03PCSI03-3    I II III  Fig. 3 – Energy scan diagram versus Cu-O distance for structure I and II, and versus Cu-O1 and Cu-O2 distances for the structure III  REFERENCES  1. S. Wang, Y. Cao, P.A. Rikvold, Phys. Rev. B 70, 205410 (2004) 2. H. Ruuska, T.A. Pakkanen, R.L. Rowley, J. Phys. Chem. 108, 2614 (2004). 3. M. Böyükata, Janson C. Belchier, J. Braz. Chem. 19, 884 (2008). 4. C. Adamo, F. Lelj, J. Mol. Struct.  (THEOCHEM) 389, 83 (1997). 5. N.A. Koryabkina, A. A. Phtak, W.F. Ruetthnger, R.J. Farrauto, F.H. Riberio, J. Catal. 217, 233 (2003). 6. Q.L. Tang, Z.X. Chen, Surf. Sci. 600, 954 (2007). 7. J. Ren, S. Meng, Phys. Rev. B 77, 54110 (2008). 8. Z. Hu, R.J. Boyd, J. Chem. Phys. 112, 9562 (2000). 9. A. Ignaczak, J. Gomes, J. Electroanal. Chem. 420, 209 (1997). 10. A. Michaelides, V.A. Ranea, P.L. de Andres, D.A. King, Phys. Rev. Lett. 90, 216102 (2003). 11. F. Jenson, Introduction to computational chemistry, 2nd Edi-tion, (John Wiley & Sons Ltd, 2007).  

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 1 No 3, 03PCSI03(3pp) (2012) 
 
 
2304-1862/2012/1(3)03PCSI03(3) 03PCSI03-1  2012 Sumy State University 
Study of the Structure Effect on Water Adsorption by a Group of Nano Copper Clusters 
 
M. Totonkoban1, M. Oftadeh1, *, N. Farzi2 
 
1 Chemistry Department, Payame Noor University, 19395-4697 Tehran, I. R. of IRAN 
2 Chemistry Department, University of Isfahan, Isfahan, I. R. of IRAN 
 
(Received 4 June 2012; published online 18 August 2012) 
 
According to the previous studies, water adsorption energy on the metal surface like as Cu strongly de-
pendent to the structure surface and the size. During the study of the mechanism of the interaction of wa-
ter and Cu in water gas shift reaction (WGSR) (CO + H2O  CO2 + H2), it has been determined Cu is ac-
tive site of catalysis. These studies inspired the authors to consider theoretically the effect of the structure 
in the process of the water adsorption in order to select the suitable structures of the copper clusters, Cu10, 
for H2 releasing in the fuel cells at B3LYP/6-31G level of theory. The results showed the distinct effect of 
the structure on the type of adsorption process (physical or chemical) through three structure of Cu10 (I, II, 
III structures, Fig. 1). The structures I and II showed physical surface adsorption in reaction with water 
and the structure III showed chemical adsorption with H2 releasing. The adsorption energies are 0.38 ,1.15 
,-28.27 (kcal/mol) and ∆Gads are 11.14, 13.49, -20.12 (kcal/mol), respectively.  
 
Keywords: Copper cluster, Watre adsorbtion, Density functional theory, Surface interaction.  
 
 PACS numbers: 34.35.+a, 34.50.Lf 
 
 
                                                          
* M_oftadeh@pnu.ac.ir 
1. INTRODUCTION  
 
Copper is an important transition metal with high 
electrical and thermal conductivity which is used in 
many industrial processes in the pure state as sheets, 
tubes, rods and wires but also as an alloy with other 
metals. In fact copper is an important material for 
structural, electrical, and electronics application [1, 2]. 
Studies show that copper clusters have three dimen-
sional interconnected structures quite different from 
solid state materials. They are aggregates of nanoscale 
size that have strange physical, chemical, structural, 
electronical and thermodynamical properties. Duo to 
broad application of metal clusters in biology, catalysis 
and nanotechnology, investigation about clusters is an 
important aspect of theoretical and experimental re-
searches. In metal clusters, bridge and hollow positions 
are important adsorption sides [3]. Analysis of transi-
tion metals complexes is critical due to specific molecu-
lar properties for systems including high amount of 
electrons and also for  study the role of ligand–metal 
interaction in catalystic processes [4]. The water gas 
shift reaction is wellknown reaction done by heteroge-
neous Cu-based catalysts that has important effect in 
H2 production for fuel cells. In this reaction Cu is active 
site of catalysis so comprehensive data about water 
adsorption on Cu surface is useful for understanding 
the WGSR mechanism [5, 6]. Previous studies confirms 
that Cu(110) is the borderline between intact and dis-
sociative water adsorption and this result could be po-
tentially useful in H2 production and its application in 
fuel cells [7]. These studies also confirm that adsorption 
energy show strong dependence on the surface struc-
ture and the cluster size [8].  
Water adsorption is outcome of transition of high 
amount of charge from water to metal. In fact molecule-
metal interaction is arising from electron  donation 
from the ligand to the metal and  back-donation of 
electrons the metal to the ligand that these interaction 
are different for various ligands and weak interaction 
of M-H2O is electrostatic interaction arising from the 
penetration of the water dipole into the metal atom 
charge cloud [4, 9].In this paper only the process of  
monomer water adsorption is studied. 
About the orientation of interaction generally it has 
been assumed that H2O absorbs "up right" with the O 
end down and OH bonds pointing away from the sur-
face, since this orientation maximizes the adsorbate 
dipole substrate image-dipole interactions [10].  
DFT method is common quantum computation 
method that energy and other molecular properties in 
ground state are accessible by applying electron proba-
bility density in ground state uniquely. B3LYP method 
is the most common function including local and non-
local terms. DFT analysis should not be done by basis 
sets lower than 6-31G. DFT methods for transition 
metals compounds like copper clusters are more relia-
ble than HF analysis [11]. 
In this paper we present the results of quantum 
mechanical studies about water adsorption process on a 
group of decade copper clusters, Cu10. This paper pre-
sents the results of Cu-H2O interaction in three Cu10 
cluster with different structures by density functional 
method. Special directionality and water adsorption 
interaction energy is studied too. 
According to the Conference policy, the proceedings 
will be published instead of the abstract book. The con-
ference proceedings will be published up to the confer-
ence sessions for the convenience of the participants 
and the best dissemination through the Web, since the 
proceedings paper will be freely available on-line. In 
order to speed up the availability of your paper online, 
the submitted manuscript must appear like ready for 
publication. So, the strict requirements to the manu-
script preparation exist. 
 
 
 
 M. TOTONKOBAN, M. OFTADEH, N. FARZI PROC. NAP 1, 03PCSI03 (2012) 
 
 
03PCSI03-2 
2. THEORETICAL METHODS AND MODELS  
 
2.1 Methods 
 
Different methods and basis set have been tested 
for Cu + (H2O)n clusters, that results with MP2 and 
medium sized basis set were in a good agreement with 
higher level methods like CCSD(T) [2]. B3LYP method 
and split valence 6-31G and diffuse 6  31 + G* basis 
sets were selected for optimization copper clusters and 
H2O. Duo to Cu is a heavy metal B3LYP/GEN was used 
for analyzing adsorption process. All of calculations 
were performed by Gaussian 09 Windows that is very 
powerful program thought the rate of analysis 
increased 4 times rather than Gaussian 03. 
 
2.2 Models 
 
The most studied cleavage planes for copper are 
(100) (111) (110). These planes have difficult properties 
atomic spacing and the adsorption energies will there-
fore be different. A surface atom on the (111) plane has 
nine coordinated atoms, six beside and three below, 
whereas a surface atom on the (100) plane has eight 
neighbors, four beside and four below. In fact (111) sur-
face has a 3-fold hollow site, whereas the (100) surface 
has a 4-fold site [6].  
Three structures of Cu10 (I, II, and III, Fig. 2)were se-
lected and made interaction with water in which the 
structures  I and II the oxygen took on-top site (upper of 
one copper atom), and in the structure III the oxygen 
located in bridge position, upper side of connection site of 
two Cu atoms.A template is a tool for enforcing a stand-
ard layout and look and feel across multiple pages or 
within content regions. It provides stricter standardiza-
tion controls of the documents. In other words, a tem-
plate is a form, or pattern used as a guide to making 
something. Due to it you do not need every time set the 
margins, spacing, page layout, fonts, format options, etc.  
 
3. RESULTS AND DISCUSSION  
 
Fig. 1 shows water adsorption process on every 
Cu10 clusters. The results of the calculated electronic 
energy, EHF, the interaction energy of water with three 
structures, Eint, the BSSE corrected interaction energy, 
Eint - BSSE, the Gibbs free adsorbtion energy, ΔGads, at 
298 K and 1 atm, the distance of the oxygen atom form 
Cu, dCu-O, and the HOH angle, < HOH, after adsorbtion 
have been listed in Table 1.  
The results indicate that the water adsorbtion on the 
structures I and II are physical adsorbtion and the spon-
taneous and chemical adsorbtion process occur for the 
structure III. In this case, water located between two Cu 
atoms as a bridge with releasing two hydrogen atoms and 
this could be a suitable model to use in fuel cells. The en-
ergy scan diagram versus Cu-O distance for the structures 
I, II and III have been depicted in Fig. 3. 
 
4. CONCLUSION 
 
In this study B3LYP method and 6-31G basis set was 
used for optimization of every cluster. Also B3LYP 
method and 6 – 31 + G* Basis set is used for water op-
timization. The studies show that BSSE correction has 
strong effect on interaction energies. The structure type 
has direct effect on type of adsorption process. All of the 
structures achieved positive frequency after optimiza-
tion. The results showed physical adsorption in water 
interaction for the structures I and II, and the other 
undergo spontaneous chemical adsorption associating 
H2 releasing. Water orientation and HOH angle change 
during adsorption process, and it is determined that 
H2O molecule get close to clusters due to the oxygen 
atom. The equilibrium distance and energies are report-
ed by single point test performance. The oxygen atom of 
water molecule located in bridge site between two Cu 
atoms of cluster and released two hydrogen atom in the 
cluster undergoing chemical adsorption. 
 
Table 1 – Results of the optimization of different structures of Cu10 and of water adsorption on different structures of Cu10 
 
< HOH 
After ad-
sorption 
d Cu-OoA 
∆Gads 
kcal/mol 
EHFBSSE 
kcal/mol 
Eads 
kcal/mol 
EHF 
Hartree 
Structure 
108.74 1.994 11.14 13.87 0.38 -16402.9410 I 
104.91 2.049 13.49 15.91 1.15 -16402.9501 II 
- - -20.12 30.10 -28.27 -16402.9706 III 
 
 
 
   
III II I 
Fig. 1 – Water adsorption on Cu10 clusters 
   
I II III 
Fig. 2 – Selected structures of Cu10 
 
 STUDY OF THE STRUCTURE EFFECT ON WATER ADSORPTION… PROC. NAP 1, 03PCSI03 (2012) 
 
 
03PCSI03-3 
 
  
I II III 
 
Fig. 3 – Energy scan diagram versus Cu-O distance for structure I and II, and versus Cu-O1 and Cu-O2 distances for the structure III 
 
REFERENCES 
 
1. S. Wang, Y. Cao, P.A. Rikvold, Phys. Rev. B 70, 205410 (2004) 
2. H. Ruuska, T.A. Pakkanen, R.L. Rowley, J. Phys. Chem. 108, 
2614 (2004). 
3. M. Böyükata, Janson C. Belchier, J. Braz. Chem. 19, 884 
(2008). 
4. C. Adamo, F. Lelj, J. Mol. Struct.  (THEOCHEM) 389, 83 
(1997). 
5. N.A. Koryabkina, A. A. Phtak, W.F. Ruetthnger, 
R.J. Farrauto, F.H. Riberio, J. Catal. 217, 233 (2003). 
6. Q.L. Tang, Z.X. Chen, Surf. Sci. 600, 954 (2007). 
7. J. Ren, S. Meng, Phys. Rev. B 77, 54110 (2008). 
8. Z. Hu, R.J. Boyd, J. Chem. Phys. 112, 9562 (2000). 
9. A. Ignaczak, J. Gomes, J. Electroanal. Chem. 420, 209 (1997). 
10. A. Michaelides, V.A. Ranea, P.L. de Andres, D.A. King, Phys. 
Rev. Lett. 90, 216102 (2003). 
11. F. Jenson, Introduction to computational chemistry, 2nd Edi-
tion, (John Wiley & Sons Ltd, 2007). 
 


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Study of the Structure Effect on Water Adsorption by a Group of Nano Copper Clusters

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