Graduate Researcher
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA, USA
Today's production of enantiopure compounds is one of the fastest growing fields of the chemical industries. The Surface Science Group at the Department of Chemical Engineering actively participates in development of novel concepts, ideas, and approaches in this vital area of the chemical engineering technology. As it was previously shown, chiral surfaces capable of enantioselectivity can be produced by cleaving single crystals of metals with the face centered cubic crystalline lattice structure along certain high Miller index planes in order to simultaneously expose both steps and kinks in the atomic arrangement of the surfaces. In particular, the enantiospecific differences have been found in adsorption properties of (R)-3-methylcyclohexanone on the chiral (643) and (653) single crystal surfaces of copper. In this project we study an entirely different class of the chiral substrates - the inorganic crystalline minerals, whose intrinsic chiral properties give them a great potential to be used in important practical applications such as enantioselective separation, adsorption, catalysis, chemical sensoring, and more. The study's primary focus is on measuring and understanding the desorption kinetics of small chiral and achiral molecules, including: (R)- and (S)-2-butanol, (L)- and (D)-alaninol, methanol, methylamine, ammonia, etc., from the naturally chiral surfaces of right-and left-handed alpha-quartz single crystals with the (1,0,-1,0), (1,1,-2,0), and (0001) face orientation using the temperature-programmed desorption (TPD) technique. Our experiments have revealed that the polar molecules do chemisorb on the surfaces of quartz, providing that the surfaces are hydroxylated, i.e. terminated with the silanol species. From the other hand, the silanol-free, or dehydroxylated, quartz surfaces appear to have a little affinity to any of the chemical substances studied. This experimental observation is fully supported by the density functional theory (DFT) calculations performed by prof. David Sholl and his group at the ChEME Department (now at the University of Georgia). The result emphesizes the importance of hydrogen bonding in interaction of polar organic molecules with the quartz surfaces. Our latest insight into the properties of such surfaces has shown that the degree of hydroxylation (and thus the structure and reactivity) depends not only on the history of the sample and conditions of the environment, i.e. the temperature and partial pressure of water, but also on the particular crystallographic plane exposed at the surface. At present, we focus our effort on understanding the specifics of hydroxylation/dehydroxylation behavior of the different quartz surfaces. This work goes in parallel with our main venue - a study of adsorption of chiral and achiral polar molecules on the naturally chiral surfaces of alpha-quartz. This work is supported by a grant of the National Science Foundation and it is guided by prof. Andrew Gellman and prof. Paul Sides. Big thanks to both of them for this great research opportunity.
Humidity influences the tribological performance of the head-disk interface in magnetic data storage devices. In this work we compare an uptake of water of the novel fullerene-like carbon nitride (FL-CNx) films with the amorphous hydrogenated carbon (a-CHy) and the carbon nitride (a-CNx) films that are commonly used as protective overcoats in computer hard disk drive surfaces. The studied carbon films were deposited on the gold plated quartz crystal substrates by a reactive dc magnetron sputtering in Ar/N2 discharges. After deposition, some of the film samples were coated with a 2-nm-thick layer of the Fomblin Z-tetraol (R), a typical lubricant used in a hard disk drive device, to mimic the real hard disk surfaces. A quartz crystal microbalance cell mounted inside of a compact high vacuum chamber was used to measure the adsorption uptake of water from a vapour phase. The experiments were performed at 323 K and at the water partial pressure corresponding to relative humidities in the range of 0% to 90%. As it has been found the water adsorption/desorption processes on the films are relatively fast, indicating that equilibrium with the ambient humidity is reached in a time scales of seconds. The amount of water adsorbed on the non-lubricated amorphous carbon films was significantly higher than that on the new fullerene-like films. The presence of the lubricant influenced water adsorption, but its impact on different carbon films was not well defined. This work was partially supported by Seagate Technology Corporation. Prof. Andrew Gellman and Dr. Esteban Broitman are acknowledged for my involvement into this interesting and educational project.
It had been postulated that for any highly-endothermic heterogeneous catalytic reaction, which utilizes a porous metal-on-insulating-oxide type catalyst, thermal energy required to run the chemical transformation can be delivered directly to the active sites of the catalyst via electromagletic microwave heating. Among a variety of examples of great practical importance of such endotermic reactions there are methane steam and dry reforming, dehydrogenation of hydrocarbons, methanol decomposition, etc. In the case when a such reaction process is perfomed with the microvave heating, both catalyst volume and reagents/products stream remain at temperatures lower than the temperature of the surface catalytically active sites. This results in a substantial improvement of the process's energy utilization efficiency. In addition, the undesired chemical side reactions, which often run in the gas volume and on the catalyst's porous support surface, are being suppressed due to the lower temperature of the medium. One major requirements for a successful realization of this concept is that the active component of the catalyst (metal particles of nanoscale dimensions) must effectively absorb the microwave radiation. In order to test the idea we studied the process of hydrogen generation from methane-containing gas mixtures over alumina-supported nickel catalysts (Ni/Al2O3). Special attention was paid to the following experimental factors: catalyst properties (i.e. surface area, metal load, preparation technique, etc.), gas stream composition, gas reactor residence time, microwave power intensity level and the type of delivery (i.e. continues or pulsed). Two pathways for the methane reaction were observed: direct microwave heating of the catalyst and the gas discharge (plasma) near the catalyst's granules rough surface. In the first case, the direct microwave heating of the catalyst facilitated the rate of hydrogen generation when compared to the conventional thermal reforming. In the second case, the microwave gas discharge facilitated formation of chemical byproducts, such as acetylene and the filamentous carbon (MWNT's). Special thanks to Dr. Yurii Aristov and Dr. Yurii Tanashev for the great experience of working on the project.
Probing ceria surface adsorption sites via reaction with molecular oxygen -- View presentation
Water adsorption from humid environments onto HDD media surface -- View presentation
Naturally chiral mineral surfaces as media for enantiospecific adsorption -- View presentation
In International Journals:
1. Vander Wal, R; Fujiyama-Novak, J; Pushkarev, V, Evolved combustion products from CNT-polymer composites. Chemical and Physical Processes in Combustion (2007), c1/1-c1/6. Publisher: Combustion Institute, CODEN: CPPCD9 ISSN: 0277-1128. Journal written in English.
2. Meghan, S; Pushkarev, V.V.; Kovalchuk, V.I.; d'Itri, J.L., The dynamic surface chemistry during the interaction of CO with ceria captured by Raman spectroscopy. Catalysis Letters (2007), 116(1-2), 41-45. Publisher: Springer, CODEN: CALEER ISSN: 1011-372X. Journal written in English.
3. Broitman, E.; Pushkarev, V. V.; Gellman, A. J.; Neidhardt, J.; Furlan, A.; Hultman, L., Water adsorption on lubricated fullerene-like CNx films. Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. Thin Solid Films (2006), 515(3), 979-983. Publisher: Elsevier B.V., CODEN: THSFAP ISSN: 0040-6090. Journal written in English.
4. Pushkarev, V.V.; Kovalchuk, V.I.; d'Itri, J.L., Probing Defect Sites on the CeO2 Surface with Dioxygen, Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, Journal of Physical Chemistry B (2004), 108 (17), 5341 -5348. Jp0311254 S1089-5647(03)01125-8, Journal written in English.
5. Reshetenko, T. V.; Avdeeva, L. B.; Ismagilov, Z. R.; Pushkarev, V. V.; Cherepanova, S. V.; Chuvilin, A. L.; Likholobov, V. A., Catalytic filamentous carbon. Structural and textural properties. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia. Carbon (2003), 41(8), 1605-1615. CODEN: CRBNAH ISSN: 0008-6223. Journal written in English.
6. Ismagilov, Z. R.; Pushkarev, V. V.; Podyacheva, O. Y.; Koryabkina, N. A.; Veringa, H., A catalytic heat-exchanging tubular reactor for combining of high temperature exothermic and endothermic reactions. Boreskov Institute of Catalysis, Novosibirsk, Russia. Chemical Engineering Journal (Lausanne) (2001), 82(1-3), 355-360. CODEN: CMEJAJ ISSN: 1385-8947. Journal written in English.
7. Ismagilov, Z. R.; Podyacheva, O. Yu.; Pushkarev, V. V.; Koryabkina, N. A.; Antsifirov, V. N.; Danchenko, Yu. V.; Solonenko, O. P.; Veringa, H., Development and study of metal foam heat-exchanging tubular reactor: Catalytic combustion of methane combined with methane steam reforming. Boreskov Institute of Catalysis, Novosibirsk, Russia. Studies in Surface Science and Catalysis (2000), 130C (International Congress on Catalysis, 2000, Pt. C), 2759-2764. CODEN: SSCTDM ISSN: 0167-2991. Journal written in English.
8. Ismagilov, Z. R.; Podyacheva, O. Yu.; Solonenko, O. P.; Pushkarev, V. V.; Kuz'min, V. I.; Ushakov, V. A.; Rudina, N. A., Application of plasma spraying in the preparation of metal-supported catalysts. Boreskov Institute of Catalysis, Novosibirsk, Russia. Catalysis Today (1999), 51(3-4), 411-417. CODEN: CATTEA ISSN: 0920-5861. Journal; General Review written in English.
9. Tanashev, Yu. Yu.; Fedoseev, V. I.; Aristov, Yu.I.; Pushkarev, V.V.; Avdeeva, L.B.; Zaikovskii, V.I.; Parmon, V.N., Methane processing under microwave radiation. Recent findings and problems. Boreskov Institute of Catalysis, Novosibirsk, Russia. Catalysis Today (1998), 42(3), 333-336. CODEN: CATTEA ISSN: 0920-5861. Journal written in English.
In Proceedings of Meetings and Conferences:
1. Carranza, Susana; Makel, Darby B.; Vander Wal, Randall L.; Berger, Gordon M.; Pushkarev, Vladimir V. Microchannel reactors for ISRU applications using nanofabricated catalysts. Makel Engineering, Inc., Chico, CA, USA. AIP Conference Proceedings (2006), 813(Space Technology and Applications International Forum--STAIF 2006), 1130-1137. Publisher: American Institute of Physics, CODEN: APCPCS ISSN: 0094-243X. Journal written in English.
2. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d'Itri, Julie L., The Chemistry of the Oxygen Storage Capacity Measurement Revisited, the 2003 Annual Meeting, Section 506d - In Honor of the Wilhelm Award Recipient (Invited Papers), November 16-21, San Francisco, CA (USA), Meeting abstract written in English.
3. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d’Itri, Julie L., In Situ Raman Spectroscopic Studies of Methanol Oxidation over CeO2, the 2003 Annual Meeting, Section 525d - Fundamentals of Oxide Catalysis, November 16-21, San Francisco, CA (USA), Meeting abstract written in English.
4. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d’Itri, Julie L., Spectroscopic Studies of Dioxygen Species on the Ceria Surface, the 2003 Annual Meeting, Section 534bb - Poster Session: Kinetics, Catalysis and Reaction Engineering, November 16-21, San Francisco, CA (USA), Meeting abstract written in English.
5. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d’Itri Julie L., Raman Spectroscopic Study of Dioxygen Species Adsorbed on the Surface of Polycrystalline CeO2, the18th North American Catalysis Society Meeting, Cancun (Mexico), June 1-6, 2003, Meeting abstract written in English.
6. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d'Itri, Julie L., In situ Raman spectroscopic studies of methanol oxidation over polycrystalline ceria. Abstracts of Papers, 225th ACS National Meeting, New Orleans, LA, United States, March 23-27, 2003, COLL-521. Publisher: American Chemical Society, Washington, DC, Meeting abstract written in English.
7. Pushkarev, Vladimir V.; d'Itri, Julie L.; Kovalchuk, Vladimir I., Raman spectroscopic study of dioxygen species adsorbed on nonstoichiometric CeO2. Abstracts of Papers, 225th ACS National Meeting, New Orleans, LA, United States, March 23-27, 2003, INOR-567, Publisher: American Chemical Society, Washington, DC, Meeting abstract written in English.
8. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d'Itri, Julie L., Evidence for CO disproportionation over ceria and ceria-zirconia: In situ Raman spectroscopic study, Abstracts of Papers, 225th ACS National Meeting, New Orleans, LA, United States, March 23-27, 2003, PETR-034, Publisher: American Chemical Society, Washington , DC , Meeting abstract written in English.
9. d'Itri, Julie L.; Kovalchuk, Vladimir; Pushkarev, Vladimir V., Probing ceria surface adsorption sites via reaction with molecular oxygen, Abstracts of Papers, 226th ACS National Meeting, New York, NY (USA), September 7-11, 2003, COLL-019, Publisher: American Chemical Society, Washington, DC, Meeting abstract written in English.
10. d'Itri, Julie L.; Pushkarev, Vladimir V.; Kovalchuk, Vladimir I., Chemical nature and reactivity of oxygen on the ceria surface: In situ Raman study, Abstracts of Papers, 223rd ACS National Meeting, Orlando, FL (USA), April 7-11, 2002, CATL-053, Publisher: American Chemical Society, Washington, DC, Meeting abstract written in English.
11. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I; d'Itri, Julie L., In Situ Raman Study of Dioxygen Adsorption and Activation on Reduced Polycrystalline CeO2 and Ce0.75Zr0.25O2, the 2002 AICHE Annual Meeting Indianapolis, Section 361f - Fundamentals of Oxide Catalysis, Nov. 3-8, 2002, November 3-8, 2002, Indianapolis, IN (USA), Meeting abstract written in English.
12. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d’Itri Julie L., In Situ Raman and FTIR Studies of CO Interaction with Ceria Containing Catalytic Materials, the17th North American Catalysis Society Meeting, Poster Session 1, Toronto (Canada), June 3-8, 2001, Meeting abstract written in English.
13. Pushkarev, Vladimir V.; Kovalchuk, Vladimir I.; d’Itri, Julie L, Interaction of CO with Palladium-Ceria-Zirconia Systems: In Situ Raman and FTIR Spectroscopic Studies, the 2001 Annual AIChE Meeting, Section 342c - Environmental Catalysis and Reaction Engineering, November 4-9, 2001, Reno, NV (USA), Meeting abstract written in English.
14. Podyacheva, O.Yu.; Ismagilov, Z.R.; Pushkarev, V.V.; Kuznetsov, V.V.; Antsifirov, V.N.; Danchenko, Yu.V.; Solonenko, O.P.; Veringa, H.J., Synthesis of combustion catalysts on metal foams by preliminary plasma coating of a gradient layer, Catalytic Combustion, San Diego (USA), April 1-16, 1999, p. 97, Meeting abstract written in English.
15. Podyacheva, O.Yu.; Ismagilov, Z.R.; Solonenko, O.P.; Pushkarev, V.V.; Plasma synthesis of thermo-stable oxide catalysts on metal supports, EUROPACAT-VI, Rimini (Italy), September 5-10, 1999, p. 847, Conference abstract written in English.
16. Podyacheva, O.Yu.; Ismagilov, Z.R.; Pushkarev, V.V.; Kuznetsov, V.V.; Antsifirov, V.N.; Danchenko, Yu.V.; Solonenko, O.P.; Veringa, H.J., Development and study of metal foam supported catalysts for catalytic heat exchangers, International Memorial K.I. Zamaraev Conference "Physical Methods for Catalytic Research at the Molecular Level", Poster Session, Novosibirsk (Russia), June 28 - July 2, 1999, p. 200, Conference abstract written in English.
17. Tanashev, Yu. Yu.; Aristov, Yu. I.; Fedoseev, V. I.; Pushkarev, V. V.; Parmon, V. N., Direct high-power irradiation of catalysts in hydrogen production from methane, Editor(s): Saetre, T.O., Hydrogen Power: Theoretical and Engineering Solutions, Proceedings of the HYPOTHESIS Symposium, 2nd, Grimstad (Norway), Aug. 18-22, 1997 (1998), Meeting Date 1997, p. 137-142, Publisher: Kluwer, Dordrecht (Netherlands), Conference abstract written in English.
18. Tanashev, Yu.Yu.; Aristov, Yu.I.; Fedoseev, V.I.; Pushkarev, V.V.; Parmon, V.N., Hydrogen production from methane via direct high-power irradiation of catalysts, Hydrogen Power: Theoretical and Engineering Solution, HYPOTHESIS II, Symposium in Grimstad (Norway), 18-22 August (1997), p.137-142, Meeting Abstract written in English.
19. Aristov, Yu.I.; Fedoseev, V.I.; Tanashev, Yu.Yu.; Pushkarev, V.V.; Avdeeva, L.B.; Zaikovskii, V.I.; Parmon, V.N., Methane processing under microwave radiation: recent findings and problems, The Third Workshop, C1-C3 Hydrocarbon Conversion, Krasnoyarsk (Russia), July 14-17, 1997, Section D1, Meeting abstract written in English.
20. Ismagilov, Z.R.; Podyacheva, O.Yu.; Pushkarev, V.V.; Rudina, N.A.; Kuz'min, V.I.; Solonenko, O.P., Application of plasma spraying in preparation of metal supported catalysts, Catalysis on Eve of the XXI Century. Science and Engineering, Novosibirsk ( Russia ) July 7-11, 1997 , Part II, p.346-348, Meeting abstract written in English.
21. Ismagilov, Z.R.; Solonenko, O.P.; Podyacheva, O.Yu.; Kuz'min, V.I.; Pushkarev, V.V.; Rudina, N.A., Some application of plasma spraying in catalysis, Proceedings of the 13th International Symposium on Plasma Chemistry (ISPC-13), Beijing (China), August 18-22, 1997, Volume IV, p.1880-1885, Meeting abstract written in English.
22. Pushkarev, V.V., Synthesis of combustion catalysts on metal supports by plasma spraying, XXXV International Scientific Students Conference, Novosibirsk (Russia), 1997, p. 21-22, Conference abstract written in Russian.
23. Aristov, Yu. I.; Fedoseev, V. I. ; Tanashev, Yu. Yu.; Pushkarev, V. V.; Parmon, V. N., Hydrogen production via direct microwave action on heterogeneous catalysts, Editor(s): Veziroglu, T. Nejat. Hydrogen Energy Progress XI, Proceedings of the World Hydrogen Energy Conference, 11th, Stuttgart (Germany), June 23-28, 1996, p. 931-938, Publisher: International Association for Hydrogen Energy, Coral Gables, Fla, Conference abstract written in English.
