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New Catalysts for Fuel Cells with Direct Ethanol Oxidation and Membrane-Electrode Assemblies on the Basis of them

28 апреля, 2011

Fuel cells (FC) with direct ethanol oxidation are promising power sources for transport and portative devices. Usage of ethanol is hampered the problems with preparation, storage and supply of fuel and also provides close ecologically clean cycle of energy transformation in nature scale.

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In “Electrocatalysis and Fuel Cells” laboratory, effective multicomponent nanosized catalysts on the different carbon supports have been developed. They are synthesized for FC cathodes and anodes as on the basis of platinum (PtМ1 M2/С, where М1 = Sn, Ru; M2 = Co, Ni, Mo, V) and without platinum (Pd, Ru-МОx/С (М= V, Ni, Cr); CoTMPP/С). Morphology of synthesized catalysts was studied by physicochemical methods (TEM, XDA, XPS). Kinetics and mechanism of current-forming reactions on these catalysts were investigated in model conditions in acid and alkaline solutions with complex of electrochemical methods (RDE, RRDE, CVA). The estimation of depth of ethanol oxidation was performed by gas and liquid chromatography methods. It was shown that depth of ethanol oxidation in acid medium on multicomponent systems is 40% and achieves 60% in alkaline medium.

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Life-cycle tests of FC with acid electrolyte. U=0.5 V.

Anode: PtSn/С. Cathode: Pt/С. 1М С2Н5ОН, O2, 750С.

For formation of membrane-electrode assemblies on the basis of suggested catalysts, the methods low-production output of MEA’s were developed. These MEA’s with active surface area up to 225 сm2 were produced with screen process printing at automated equipment EKRA. The testing of FC prototype model is performed on specialized equipment of world level, Arbin and ElectroChem test setup.

Head of  the Laboratory of Electroсatalysis and Fuel Cells, professor, Doctor of Science (Chemistry) Mikhail Romanovich Tarasevich


Three-Metallic Nanosized Systems for Cathodes of Fuel Cells and Membrane-Electrode Assemblies on the Basis of them

28 апреля, 2011

Widespread development and commercialization of fuel cells require considerable lowering the amount used platinum in cathodic catalysts. One of the ways of such a lowering consists in usage of bi- and three-metallic systems instead monoplatinum catalysts.

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Parameters of membrane-electrode assemblies for monoplatinum catalyst and two three-metallic systems demonstrated the possibility of lowering the amount used platinum

The usage of bi- and three-metallic systems, moreover, gives rise to significant increase of cathodic catalyst stability. It can be connected with the formation of core-shell structures as in the process  of chemical pretreatment of catalysts and their electrochemical potential cycling.

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Discharge parameters of hydrogen-air fuel cell with 20PdCo5Pt cathodic catalyst at the different loading of metallic phase (m.ph.). Membrane Nafion 212, 65ºС, gas pressure 1 atm. Anode: 20Pt/С (HiSPEC) 0.2 mg m.ph./сm2.

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Microphotographs of 30PtCoCr/С (a) and 20PdCo5Pt (b) catalysts and their histograms.


Head of  the Laboratory of Electroсatalysis and Fuel Cells, professor, Doctor of Science (Chemistry) Mikhail Romanovich Tarasevich


Non-Containing Precious Metals Cathodic Catalysts for Proton Exchange Membrane Fuel Cells and Membrane-Electrode Assemblies on the Basis of them

28 апреля, 2011

The high cost and scarcity of platinum which just now is the most active cathodic catalyst for low-temperature fuel cells with proton exchange membrane induce all over the world the constant search and development of nonplatinum active and stable enough catalysts.

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The parameters of H2-O2 5 cm2 square fuel cell. Membrane: Nafion 212. Cathode: X/С 4.0 mg cat./ cm2. Anode: Pt/C (E-TEK) 0.2 mg Pt/cm2. Gas humidity: 95%. MEA’s testing were performed with ElectroChem. test setup.

The Figure on the left presents the results of search of such a catalyst tested in hydrogen-oxygen fuel cell. Discharge curve shows that the value of current density at E=0.6 V achieves 0.4 A/cm2. The dependence of specific power on current density shows the maximum at 350 mW/cm2.

In the laboratory it was shown that platinum-like dependence of kinetic parameters of oxygen reduction reaction on pH is the most important test program for the evaluation of cathodic catalysts. From the Figure represented below it follows that the behaviour of E1/2-pH dependence for a new catalyst (conditionally denote here as Х/С) is identical to the dependence for platinum that speaks about prospectivity of the new system. Meanwhile for carbon material, E1/2 independence of pH practically takes place. Moreover, XPS on initial catalyst (а) and after its treatment in sulfuric acid during 50 h (b) show high enough stability of the new catalytic system.

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pH dependence of half-wave potential for oxygen reduction reaction

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XPS for N 1s of X/C initial system (a) and after the treatment in sulfuric acid during 50 h

Head of  the Laboratory of Electroсatalysis and Fuel Cells, professor, Doctor of Science (Chemistry) Mikhail Romanovich Tarasevich


Nanocomposite (nc) silver (ag) – sulpho-cation exchanger and sorption of the oxygen (with its removal from water)

3 марта, 2011

In a number of the NanoComposites (NC): Metal – ion exchanger

Me – component is distributed along the porous ion exchange matrix almost uniformly.

Scheme 1. shows the ion exchanger bead (a) and the Me – location for both places : as in the bead pores (5, a) ; so for the pore surfaces (5, b). ( Metals are imaged as cross-hatched on the Scheme 1. (a, b) ).  Me-component occupies the separate areas localized near the ionogenic groups (b)

(a)                                           (b)

Scheme 1

Scheme 1. Representation of the ion exchanger bead (a, left) an the fragment the pore (b, right) for the Me-containing NC: 1 – polymeric chain (R), 2 – micropore, 3 – fixed groups ( -SO3- ), 4 – counter-ion, 5 – Me0 – center (Cu0).

According  to the  microscope  monitoring NanoComposites contain  the Me – NanoParticles with the variation of the size values from 20nm till 500nm.

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Examples for NC (Me – sulpho-cation-exchanger: KU-23 (Ukraine)) are presented on Figs  1:

( I NC, Me0 = Cu0 )     &      ( IINC, Me0 = Ag0 )

( INC, Me0= Cu0 ) – NC : Cu0 – KU-23 in  dependence  of  the number of the cycle (n)  for saturation – reduction  in the process of  the NC formation ( reduction agent – Na2S2O4 ) :

n = 1 n = 2 n = 5 n = 10

Fig 1

( IINC, Me0= Ag0 ) – NC: Ag0 – KU-23  in dependence  of  the  reducing  agents  (a), (b), (c) :

(a) - Na2S2O4 (b) - Na2S2O4 (c) – N2H4

Fig.  2.   MicroPictures  of  the NC  bead  cutoff  (magnification – 10 000), and                Me - NanoParticles Content  Distributions: ( I – NC, Me0= Cu0 ) &  ( II – NC, Me0= Ag0 )

Fig. 1. MicroPictures of the NC bead cutoff (magnification – 10 000), and Me – NanoParticles Content Distributions: ( I – NC, Me0= Cu0 ) & ( II – NC, Me0= Ag0 )

It is shown  that the Me – NanoParticles size  in the resin bead (Fig. 1) is  significant.

Such NanoMaterials as the NC are interesting due to the enhanced activity of the NanoSized Metal, and  to the  combination of the electrone- (redox-) and IEx  properties. This  combination makes the NC as effective sorbents, in particular, for the removal of the soluble oxygen  during the process of  water-conditioning.

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Nature of  the Me-component  in  the NC ( Me0 = Cu0 (a) and Me0= Ag0 (b)) determines Parameters  of the multi – stage  Process with the participation of  such  NanoMaterials.

Figs. 2 show the oxidation Process (to the moment for 40% of  the oxidation).

(a) Cu0 ; Cu2+ ß Cu0_KU23 (b) Ag0 ; Ag+ ß Ag0_KU23

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Fig. 2. Micropictures  of   the NC-bead cutoff :  Copper Cu0 , (a, left )  & Silver Ag0 (b, right ) containing NC.  To the left  (a) – moving (during the Process) boundary   between Cu0 and  Cu2+ states in the bead.

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(a) Fuji  CS-07  (Japan)                          (b) Duolite  A 365  (USA)

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(c) AV-17-10 P_g   (Russia)                           (d) AV-17-8  (Russia)

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Fig. 3 (a-d). Micropicture  of   the silver containing (Ag0 )  bead cutoff  for NC, obtaining by the authors on the basis of  the various  anion exchangers (a – d).

Principal researcher of the Laboratory of Physicochemical Principles of Chromatography and Gas Chromatography–Mass Spectrometry, Anatoliy Iv. Kalinitchev, Doctor of Science (Chemistry)


Alternative method of obtaining 99mTc for the medical purposes

28 февраля, 2011

In connection with the curtailment by Canada the deliveries of the fragmentation of 99Mo into the different countries of peace, arose the problems with obtaining of 99mTc for conducting diagnostics in medicine.    In essence, practical medicine is ensured 99mTc, in an obtained sorption manner with the use of fragmentation of 99Mo.   Obtaining 99Mo from irradiated uranium – this is the labor-consuming, complex and expensive work, which requires deep removal of large number of radioactive admixtures from molybdenum. Therefore in [IFKHE] RAN [Russian Academy of Science], g. Moscow was developed the cheaper, simpler method of industrial obtaining of 99mTc from 99Mo and was created extraction centrifugal [poluprotivotochnyy] [generator]99mTc.   In the radium institute [im]. [V].[G].[Khlopina] g. Saint Petersburg obtains 99mTc using the method in question. At the basis of the method of the separation of 99Mo and 99mTc lies the process of the extraction of 99mTc from the alkaline solution of molybdenum by methylethylketone.    Initial product in this technology is the natural or enriched isotope of 98Mo, in which after irradiation in the nuclear reactor is accumulated 99Mo. This method of obtaining provides the high [radionuklidnuyu] cleanliness of 99mTc, since the possibility of the pollution of end product by the radio-toxic admixtures, such as are 131I, 103Ru, 95Zr, 188 Re and other, is excluded Each party [RFP] passes thorough checking, while eluate from the sorption generator daily checking in the clinics it does not undergo.   The technological process of the industrial production of 99mTc is neglected in “scientific production association radium institute [im]. [V].[G].[Khlopina]” [g].[Sankt]- Petersburg in 1993. and 25 clinics of city are ensured by technecium on the present time. In 2007 began the industrial production of 99mTc of medical designation at the plant “[Medradiopreparat]” in g. To Moscow, which also is used in the clinics for the diagnostic purposes.

The fundamental characteristics of the generator of 99mTc are given below:

  • the summary activity of initial [radionuklidnoy] mixture 99[Mo] – 99mTc it can compose order 30 Curie;
  • radiochemical cleanliness exceeds 99%;
  • the time of the extraction isolation of 99mTc 6-8 min.;
  • the output of end product is not less than 95%;
  • the volume of extract is within the limits of 40- of 50 ml;
  • the content 99[Mo] in the end product is not more than 10-5%;
  • concentration MEK in the solution of 99mTc is not more than 0,04[mg]/[ml];
  • the values of [rN] of the aqueous solution of 99mTc be within the limits of 6,0 -7,0;
  • volumetric activity can be obtained it is 5th 10 [GBk]/[ml];
  • total time of the final product is less than 90 minutes.

Technecium – 99[m], produced on our technology, on the quality exceeds, and on the cost is lower than technecium, obtained by sorption method.

Overall dimensions of the extractor:  a height – is 400 mm; diameter – 200 mm; weight – about 15kg.

The generators of technecium – 99[m] is prepared from the stainless steel of high quality. The developed by us technologies of obtaining radionuclides 90Y, 99mTc, 188Re can compose competition to world firms, which work in this the field, and the created generators are protected by 9-[yuavtorskimi] evidence of the USSR and by 5-[yupatentami] RF.
The respected associates, proposed to technology give the possibility to ensure the cities largest on the number with the radionuclides indicated. We propose collaboration in different aspects of problems described above and, in the case of the appearance in you of an interest, they are ready to discuss all technical and financial questions. We would want to obtain answer to our proposal on the electronic mail from you (Contact face: Alexander [Filyanin], e-mail: filyanin@ipc.rssi.ru).

On the industrial production of high purity 90Y, 99mTc and 188Re radionuclides for medical purposes using centrifugal semicountercurrent extraction generators

10 февраля, 2011

Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences (IPCE RAS) developed the extraction technologies, created the generators based thereupon, and possesses the relevant “know’how” to produce the following radionuclides:

90Y, 99mTc, and 188Re.

Centrifugal Extraction Generators-General View

99mTc and 188Re generators are made of stainless steel.

The technologies we developed for the production of 90Y, 99mTc, and 188Re are highly competitive to the worldwide known companies working in the area. Our works on this subject are protected by 14 patents of Russia.

We propose the cooperation in various aspects of the problems described above. We could also look at the possibility to produce other radiopharmaceuticals, e.g. cyclotron isotopes, using our centrifugal generators. In case you have an interest, we are willing to discuss all the associated technical and financial issues.

Yttrium – 90

Yttrium – 90 The technique for producing 90Y from 90Sr using a centrifugal extraction generator is of the major practical interest. The developed generator consists of the two connected in series 2-stage centrifugal extractors. The first unit is used for the separation of 90Y from 90Sr at the first stage and for washing the 90Y extract at the second stage. The D2EHPA extractant feed rate is up to 1000 cm3/hr. The second unit is used for the deep purification of 90Y from 90Sr and 90Y stripping. After the 90Y re-extract is evaporated the final product is obtained in the chloride form (0.1M HCl).

To date we have accumulated a 5-year experience of the centrifugal semicountercurrent extraction generator application for radiopharmaceutical purposes at the Institute of Biophysics, Moscow (Dr. Kodina G.E. is the Head of Laboratory). An extraction facility for the production of medicinal 90Y isotope according to the technological scheme developed by us has successfully commenced its operation in 2000 at the Institute for Nuclear Physics of Czech Republic.

The technique for 90Y separation described above offers the following advantages as compared to the other well-known methods (see J. Radiation Appl., vol.41, #9, pp.861-865, 1990):

  • the equipment (generator) capacity ranges very wide from trace quantities to several dozens of Curie per 1 cycle;
  • the final product yield amounts not less than 95%;
  • the 90Sr impurity does not exceed 10‑5‑ 10-6% at the date of calibration;
  • the separation process can be accomplished within a 30-60 min period (time for evaporation not included) whereas the other known methods could be done within 20-24 hrs;
  • the extract volume is 50 cm3.

The generator is made of niobium metal.

Technecium – 99m

As well, we have developed a technique for the industrial production of 99mTc for medical purposes based on a centrifugal extractor with MEK (methylethylketone) for an extractant. A molybdenum trioxide target enriched by 98Mo irradiated in a nuclear reactor is used for the recovery of 99mTc. The summary activity of  radionuklide mixture 99Mo – 99mTc can compose 30 Curie and more. A technological process of the industrial production of 99mTc based on a centrifugal extraction generator has been started in Saint Petersburg, Russia in 1993 and 25 clinics of the city are provided with 99mTc ever since. The industrial production of technecium – 99m began also in 2005 at the plant “Medradiopreparat” in Moscow on our technology and the clinics of Moscow are ensured them.

The basic parameters of a 99mTc generator are listed below:

  • the summary activity of initial [radionuklidnoy] mixture 99[Mo] – 99mTc it can compose order 30 Curie;
  • the period of time needed for the 99mTc extraction separation is about 6-8 min;
  • the final product yield amounts not less than 95%;
  • radiochemical purity exceeds 99%;
  • the extract volume is 50 cm3;
  • the 99Mo content in the final product does not exceed 10-5%.
  • concentration MEK in the solution of 99mTc is not more than 0,005[mg]/[ml].
  • pH of the 99mTc aqueous solution is within the range of 6.0-7.0
  • volumetric activity can be obtained it is 5th 10 [GBk]/[ml].
  • the total time of receipt of the final product is not more than 1,5 hours.

The quality of 99mTc solution obtained according to our technique is as good as the similar solution obtained according to the sorption technique.

Renium – 188

One of the promising isotopes for therapy of a number of diseases in nuclear medicine is 188Re. A facility for producing the isotope has commenced its operation in Khlopin’s Radium Institute. The selected optimum operation conditions resulted in the following:

  • 188Re yield exceeds 90%;
  • radiochemical purity exceeds 99%;
  • pH of the 188Re aqueous solution is within the range of 6.5-7.0;
  • the extract volume is 50 cm3;
  • the period of time needed for the 188Re extraction separation is about 6-8 min;
  • activity of 188W did not exceed 1.10-6 of 188Re; the solvent was MEK.
  • the total time of receipt of the final product is not more than 2 hours.

Basically the above mentioned isotope is obtained in sorption generators; those need 188W produced in the high-flux reactors with the neutron flux over 1.1015 n.cm-2s-1, and, ultimately, that yields the high cost of the final 188Re. For the production of 188Re on an extraction centrifugal generator the natural tungsten could be used for the target material followed by the irradiation in a medium-flux reactor. That gives the cost of 188Re compared to that of 99mTc. The developed technology and equipment enable the feed 188W solution up to 5 Ci and resulting 188Re solutions of high specific activity and very low content of inorganic contaminants. The latter is very important when introducing 188Re into antibodies and peptides.

Dimensions of a 2-stage extraction unit are the following:

  • height – 400 mm;
  • diameter – 200 mm;
  • weight – about 15 kg.



Novelty book «Nanocomposity metal – ion exchanger»

17 апреля, 2010

THE MONOGRAPH  T.Kravchenko (VSU), L. Polyanskiy (VSU), A.Kalinitchev (IPСE RAS), D.Konev (VSU) “NANOCOMPOSITY METAL – ION EXCHANGER”. Voronezh State University (VSU), 2009 – M.: “Nauka” ( “Science” ), 391p.

The Monograph is approved for publication by two Scientific Councils :
A.N. FRUMKIN Institute of Physical Chemistry & Electrochemistry RAS, VORONEZH State University

Book

Annotation

  • Energy saturated Nano Composites ( NC ) materials: “Metal – ion exchangers” are considered in  the  Monograph.  The Nano Composites are used  for  the  intensification  of   the chemical, electrochemical  and  sorption processes  in NanoScience.
  • There  are underlined advantages of the ion exchange (IEx) matrixes for the  chemical directional synthesis, stabilization of the Metal NanoParticles (NP) and realization of the desired process in the NanoPorous space of the matrixes.
  • It  is  systematizated and generalized the available information  concerning known classes of the NC Metal – ion exchangers.
  • For  the  first time in the full size there are presented the fundamental physico-chemical basis of the redox-sorption, which play the definite role in the  generation and application of  the NC Metal-ion exchangers as the sorbents : thermodynamics, macrokinetics and dynamics. It is shown the accelerating operation of the Nano-Sized factors.
  • The  are given the theoretical reasons  of the sorption methods with  the NC usage and described the installations for the economical and ecological advisable removal of the molecular oxygen from liquids  and gases including concentrating of heavy metals from the complex compositions in solutions.

For  the specialists  in the field of the physical chemistry  of the NanoSystems, sorption and oxidation-reaction processes and technology for water treatment, removal of the oxygen from gases, corrosion protection, recovery and concentrating of Metals, environmental protection.

Principal researcher of the Laboratory of Physicochemical Principles of Chromatography and Gas Chromatography–Mass Spectrometry, Anatoliy Iv. Kalinitchev, Doctor of Science (Chemistry)


Photorefractive (PR) polymer composites

25 ноября, 2009

A number of photorefractive (PR) polymer composites has been developed.They are based on crawn-substitutedphthalocyanines ruthenium, which is unique because they are able to amplify laser beams, infrared, up to 1600 nm. New composites arecreated on the base ofpolyvinylcarbazole (PVC) with the photovoltaic (PV) and photorefractive (PR) sensitivity for wavelengths of telecommunications range (laser IS550-120 with continuous emission at 1550 nmhas been used).

Joint work in the framework of the unified theme: a Laboratory of New Physicochemical Problems, academic AslanYusupovichTsivadze, D.Sc. Yu.G. Gorbunova, Ph.D.Yu.Yu.Yenakieva and the Laboratory of Electronic and Potonic Processes in Polymer Nanomaterials, Prof. Anatoly VeniaminovichVannikov


The principles of a superhydrophobicnanocomposite coatings

22 октября, 2009

The principles of a superhydrophobicnanocomposite coatings by depositing nanoparticles dispersions have been developed on the basis of theoretical analysis of the forces that determine the aggregation in the bulk of multi-component dispersions and in wetting films of the dispersions. The perspective projection of obtaining surface texture necessary for  achieving of superhydrophobic states on the basis of directed aggregation of nanoparticles have been shown, which have not been previously possible. As it has been established dispersions with non-polar or weakly polar media and uncharged nanoparticles are the most appropriate for obtaining superhydrophobicnanocomposite coatings.

Head of the Laboratory of Surface Forces, Dr. Sc.Alexander M. Emelianenko, principal researcher, Associated member of the RAS Lyudmila B. Boynovich


The concept of electron-beam non-waste recycling renewable non-food plant material into components of motor fuel

17 сентября, 2009

The concept of electron-beam non-waste recycling renewable non-food plant material into components of motor fuel and heavy organic semi- chemicals, consisting in the destruction of ligno-cellulosic materials under electron radiation dose rate 1-6 kGr / s and the radiative heating has been developed. The optimal circulation processing mode, which provides about 75% conversion of plant material in anhydrous liquid motor fuel with the yield of more than 15 kg / kW × h has been found. The synergistic effect of increasing of the organic liquid yield  from mixtures of vegetal and synthetic polymers, which opens up the prospect of recycling plastic waste and obtaining useful products.

Head of the Laboratory of Radiation Chemistry, Prof. Igor E. Makarov


 
 
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