XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
258
T3: P–4
Ni, Cu-containing metal oxide coatings on aluminum and titanium:
XPS study
Elena Koblova
1
, and Alexander Ustinov
1,2
1
Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 159, Prosp. 100-
letiya Vladivostoka, Vladivostok, 690022, Russian Federation, e-mail: les@ich.dvo.ru
2
School of Natural Sciences, Far Eastern Federal University, 8, Sukhanova Str., Vladivostok,
690091, Russian federation
The present research work was devoted to the investigation of the Ni, Cu-containing metal
oxide coatings formed by the method of plasma electrolytic oxidation on aluminum and
titanium. The elemental composition, structure and chemical states of the elements of the
surface and subsurface layers were determined using X-ray photoelectron spectroscopy (XPS).
A wide range of metal oxide coatings were studied at different stages of formation [1]. As well
as these coatings exhibit a certain catalytic activity in the oxidation of CO to CO
2
, factors
affecting the catalytic activity of the coatings were determined. The obtained results point to the
similar patterns in the composition and significant differences in the structure of the formed
coatings.
Obviously, besides the base metal, the studied coatings contain various amounts of the
electrolyte components and elements of the atmosphere. During the oxidation process a layer
mainly consisting of various oxides and phosphates is formed on the metal substrate. Namely,
oxides and phosphates of Al or Ti as well as oxides and phosphates of Ni and/or Cu, together
with the spinel type structures are observed.
The obtained results indicate that the catalytic activity of the investigated coatings strongly
depends on their composition and structure. By XPS method, which showed a great efficiency in
the investigations of the metal oxide coatings and allowed to determine the nature of catalytic
activity, it was found that a decisive role in the catalytic activity is played by the ratio of oxides
and phosphates in the coatings. Thus, the greater incorporation of phosphorus in the coatings
formed on titanium and, accordingly, phosphates of the base metal and especially 3d elements
(Ni and Cu) causes a smaller catalytic activity in the oxidation of CO to CO
2
of the Ni, Cu-
containing metal oxide coatings formed on titanium in comparison with the similar coatings
formed on aluminum [2, 3]. In addition, the greater catalytic activity of the Ni-containing
coatings in comparison with the Cu-containing coatings is due to the different incorporation of
nickel and copper, and their multidirectional diffusion at high temperatures of the oxidation
process.
Keywords: metal oxide coatings; X-ray photoelectron spectroscopy; oxidation of CO to CO
2
References
[1] E.A. Koblova., A.Yu. Ustinov, V.S. Rudnev, I.V. Luckiyanchuk, I.V. Chernykh, J. Struct. Chem. 58
N6 (2017) in press.
[2] Koblova E.A., Ustinov A.Yu., Chernykh I.V., Luckiyanchuk I.V., Rudnev V.S. Vestnik FEB RAS. N4
(2015) 39.
[3] Koblova E.A., Ustinov A.Yu., Chernykh I.V., Luckiyanchuk I.V., Rudnev V.S. Proceedings of the
Southwest State University. Technics and Technologies. N1 (2016) 130.
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
259
T3: P–5
Studies of Zn(II), Fe(II) and Ag(I) complexes of 2,2´:6´,2´´-terpyridine
adsorbed on Ag nanoparticles surfaces by SERS spectroscopy,
factor group analysis and DFT calculations
Irena Matulková
1
, Peter Mojzeš
3
, Marek Procházka
3
, Blanka Vlčková
2
,
and Ivana Šloufová
2
1
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030/8, 128
40 Prague 2, Czech Republic, e-mail: irena.matulkova@natur.cuni.cz
2
Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University,
Hlavova 2030/8, 128 40 Prague 2, Czech Republic
3
Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16
Prague 2, Czech Republic
The 2,2’:6’,2”-terpyridine (tpy) is, owing to its high binding affinity towards transition metal
ions, commonly used as an end-group in building blocks of oligomers that after the
complexation with transition metals form metallo-supramolecular polymers and dynamers [1–3].
The surface-enhanced Raman scattering (SERS) [4] spectroscopy is widely used for a study of
very low concentration of adsorbates. SERS spectroscopy enables us to investigate transition
metal complexes in highly diluted solutions, which overcomes the problem of their limited
solubility.
In our previous study, two spectrally
different forms of tpy in Ag NPs/tpy systems
were observed [5]: ionic Ag
+
-tpy, spectrally
identical to [Ag(tpy)]NO
3
and nonionic Ag
0
-
tpy, spectrally identical to [Fe(tpy)
2
]
2+
complex, in which the metal-to-ligand charge
transfer transition takes place [6]. In the
present study, the SERS spectroscopy
supported by factor analysis and DFT
calculations were employed in probing of the
adsorption ability and the stability of Ag(I),
Zn(II) and Fe(II) complexes of tpy on AgNP
surfaces. While the kinetic studies of
interactions of tpy complexes with Ag NP
surfaces proved the stability of [Fe(tpy)
2
]
2+
,
the surface-induced conversion of [Zn(tpy)
2
]
2+
into Ag
+
-tpy together with conversion of Ag
+
-
tpy surface species into Zn
2+
-tpy upon addition
of Zn
2+
ions in the system have been revealed.
Keywords:
surface-enhanced
Raman
scattering
(SERS)
spectroscopy;
Ag nanoparticles;
2,2′:6′,2″-terpyridine
(tpy)
Acknowledgment
This work was supported by the Czech Science Foundation (Grant No. 17-05007S).
References
[1] J.M. Lehn, Supramolecular Chemistry, Concepts and Perspectives, VCH, Weinheim, Germany, 1995.
[2] A. Winter, M.D. Hager, G. R. Newkome, U.S. Schubert, Adv. Mater. 23 (2011) 5728.
[3] P. Bláhová, J. Zedník, I. Šloufová, J. Vohlídal, J, Svoboda, Soft Mater. 12 (2014) 214.
[4] R. Aroca, Surface-Enhanced Vibrational Spectroscopy, John Wiley and Sons, Ltd., Chichester, UK,
2006.
[5] I. Šloufová, M. Procházka, B. Vlčková, J. Raman Spectrosc. 46 (2015) 39.
[6] I. Šloufová, B. Vlčková, M. Procházka, J. Svoboda, J. Vohlídal, 45 (2014) 338.
Fig. 1. The factor analysis of the SERS signal
of Ag
+
/Fe
2+
ionic exchange in tpy complexes
on the AgNP surface.
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