“Quantum Theory Calculations of Supported and Unsupported Transition-Metal Clusters”, presented at http://3whpc.lcca.usp.br

1. Quantum Theory Calculations of
Supported Transition-Metal
Clusters
Dr. Yohanna Seminovski Perez,
Dr. Polina Tereshchuk,
Prof. Dr. Juarez L. F. Da Silva
QTNano Quantum Theory of Nanomaterials Group
São Carlos Institute of Chemistry
University of São Paulo

2. Members:
-Prof. Dr. Juarez L. F. Da Silva
-Posdocs: Dr. Yohanna Dr. Polina Dr. Anderson S.
Seminovski Tereshchuk Chaves
-PhD students: Rafael L.H. Diego G. Fernando P. Celso R.
Freire Sobrinho Sabino Rego
-Msc students: Larissa Z. Israel Douglas G. Rafael
Besse Rosalino de Souza Besse
Computational Resources:
- Local SGI cluster
- LCCA Aguia cluster
- USP-Rice Bluegene
Collaborators:
- Prof. Dr. Adam Kiejna, U. Wrocław, Poland
- Prof. Dr. Maurício J. Piotrowski, UFPel, Brazil
- Prof. Dr. Luiz Nunes de Oliveira, IFSC, USP, Brazil
- Prof. Dr. Marcelo Falcão de Oliveira, EESC, USP, Brazil
Quantum Theory of
Nanomaterials Group

3. Research Projects
Clusters and Nanoclusters
- Transition-metals.
- Oxides and binary systems.
- Global optimization algorithms.
- Thermodynamic properties.
Surfaces
- Clean surface properties.
- Transition-metal supported on surfaces.
- Molecular adsorption on surfaces.
Solids
- Transparent conducting oxides.
- Wide-band gap semiconductors.

4. Computational Details
Density Functional Theory – DFT
- Semilocal XC functionals: PBE, PW91.
- Hybrid functionals: PBE0, HSE.
- Orbital dependent LDA+U functional.
- van der Waals corrections (S. Grimme, TS-SCS).
- Spin-orbit coupling for valence states.
Kohn-Sham equations
- Plane waves: VASP.
- Numeric atom-centered basis functions: FHI-AIMS.
Local and Global optimizations algorithms - GOP
- Revised Basin Hopping Monte Carlo – RBHMC.
- Genetic Algorithm - GA.

5. Importance and Challenges of TM/CeO2
(111) supports
● This interfacial interaction can be theoretically described.
Importance and Challenges of TM/CeO2
(111) supports are related with Ce atom:
● The conditions in which this happens are going to be described using DFT+U approach.
● In VASP DFT code, we used an effective U, Ueff=4.5 eV within the Dudarev approach of
DFT+U.
CeO2
Metal Oxide Support
TM Cluster
BSASBS
● TM/CeO2
(111) supports have a characteristic synergistic effect useful for catalysis of
reactions.
Interface
Synergy
Ce-4f valence state is delocalized in unreduced CeO2
(111), but
these states can also allocate strongly correlated localized charges.

6. TM4
/CeO2
(111): 2D vs. 3D TM over CeO2
Ru4
/CeO2
(111)
Rh4
/CeO2
(111)
Os4
/CeO2
(111)
Ir4
/CeO2
(111)
Pd4
/CeO2
(111)
Pt4
/CeO2
(111)
Ag4
/CeO2
(111)
Au4
/CeO2
(111)
M.J. Piotrowski, P. Tereshchuk, J.L.F. Da Silva, J. Phys Chem C 118 (2014) 21438
2D-Monolayer
- In TM 2D-Monolayer: there is an equidistant CeIII
generation.
- In TM 3D-Cluster: Generation of one CeIII
for Pt and Pd and two for Au and Ag.
3D-Cluster
Transition Metal of
group 6 and 7
Partially filled
d-orbitals
Transition Metal of
group 8 and 9
Almost completely
filled d-orbitals
For Pd and Pt cases (8 group):
For Au and Ag (9 group):
For Ru,Rh,Os and Ir:

7. Pt4
/CeO2
(111): Electronic structure
electronic LDOS of CeIII
states
TM states hibridized with O states
M.J. Piotrowski, P. Tereshchuk, J.L.F. Da Silva, J. Phys Chem C 118 (2014) 21438

8. P. Tereshchuk, R.L.H. Freire, C.G. Ungureanu, Y. Seminovski, A. Kiejna, J.L.F. Da Silva, Phys.
Chem. Chem. Phys. (2015) DOI: 10.1039/C4CP06016D
13-atoms TM-clusters (TM13
)
A 4x4 unit-cell of unreduced
CeO2
(111) surface
● CeIII
are slightly bigger than
CeIV
creating some strains in
the surface.
3D-Pyramidal structure 2D-Structures
TM13
/CeO2
(111): 2D vs. 3D TM over CeO2
3 CeIII
are located in
the topmost Ce layer.
TM13
of Ag, Au, Pt and Pd show a
pyramid like structure as the most stable.
Calculations:
Erel=Most stable Erel=

9. Flow of electronic charges on TM13
/CeO2
(111)
TM13
-cluster stacking:
TM/TM4
/TM8
/CeO2
(111)
P. Tereshchuk, R.L.H. Freire, C.G. Ungureanu, Y. Seminovski, A. Kiejna, J.L.F. Da Silva, Phys.
Chem. Chem. Phys. (2015) DOI: 10.1039/C4CP06016D
3- Ce f-states change from
itinerant to localized
(from CeIV
to CeIII
)
4- Important to notice is that
the pressure of the TM13
-
clusters decreases the charge
of the underlying O-ions and
increases in the remaining O-
ions.
e-
e-
e-
1- Flow of electronic charge
from TM13
cluster to CeO2
(111) due to
electronegativity-difference.
2- Induce a change in the
oxidation-state of 3 Ce-
atoms in the topmost-Ce
layer.

10. ● In TM4
/CeO2
(111) the 2D and 3D TM structures have an atomic
arrangement due to the interaction with the surface, which
electronic LDOS shows TM states hibridized with the O states and
also the formation of localized CeIII
.
● In TM13
/CeO2
(111) there is a formation of a pyramid-like structure
with a TM/TM4
/TM8
/CeO2
(111) stacking in which the charges flow
from the TM8
-layer to the CeO2
(111) surface and the effective-
cationic-charge change in 3 Ce-atoms.
Conclusions

11. Publications
● P. Tereshchuk, R.L.H. Freire, C.G. Ungureanu, Y. Seminovski, A. Kiejna, J.L.F. Da Silva, Phys.
Chem. Chem. Phys. (2015) DOI: 10.1039/C4CP06016D
● A.S. Chaves, G.G. Rondina, M.J. Piotrowski, J.L.F. Da Silva, Computational Materials Science 98
(2015) 278.
● P. Tereshchuk, M.J.Piotrowski, J.L.F. Da Silva, RSC Advances 5 (2015) 521.
● F.P. Sabino, L.N. de Oliveira, J.L.F. Da Silva, Physical Review B 90 (15) (2014) 155206.
● A.S. Chaves, G.G. Rondina, M.J. Piotrowski, P. Tereshchuk, J.L.F. Da Silva, The Journal of Physical
Chemistry A 118 (2014) 10813.
● M.J. Piotrowski, P. Tereshchuk, J.L.F. Da Silva, The Journal of Physical Chemistry C 118 (2014)
21438.
● R.L.H. Freire, A. Kiejna, J.L.F. Da Silva, The Journal of Physical Chemistry C 118 (2014) 19051.
● P. Tereshchuk, A.S. Chaves, J.L.F. Da Silva, The Journal of Physical Chemistry C 118 (2014) 15251.
● P. Tereshchuk, R.L.H. Freire, J.L.F. Da Silva, RSC Advances 4 (2014) 9247.
using local, LCCA, and blue-gene resources
Thank you!
from 2014 and up to now 9 publications