In recent years, sustainable “green” processes have received considerable attention, because the use of environmentally friendly solvents and decreased energy consumption became requirements for the chemical industry in many countries [1, 2]. It is already well established that catalytic nanoparticles (NPs) possess unique catalytic properties, due to large surface areas and a considerable number of surface atoms, leading to an increased amount of active sites [3–5]. The catalytic properties of NPs depend on the NP size, NP size distribution, NP environment, etc. . All of these parameters can be controlled if NPs are formed in nanostructured polymeric matrices, which serve as templates or nanoreactors for NP formation [7–9]. The majority of nanostructured polymers for catalytic applications are presented by amphiphilic block copolymers [10–14], dendrimers [15–17], multiple deposited polymer layers  and nanoporous polymers [19, 20]. The formation of nanoparticulate catalysts, using nanoporous polymers, seems to be especially appealing, because incorporation of metal compounds can be achieved by simple impregnation followed by reduction or oxidation depending on the catalyst type.
Hypercrosslinked polystyrene (HPS) is a typical representative of porous polymers formed, due to polymer crosslinking in a good solvent [21, 22]. Due to a high crosslinking density, which can exceed 100%, HPS consists of rigid pores, the sizes of which depend on the preparation conditions. Commercial HPS  can contain micropores, along with small and large mesopores or even macropores. These larger pores are intentionally designed to facilitate the mass transport of reagents and target products . In our preceding work, the HPS samples containing micro-, macro-, or mesopores were successfully used as a polymeric matrix controlling NP formation and as a support for catalytic NPs [19, 25–27]. Considering that the catalytic properties of NPs are size dependent [28–30], an optimal particle size, which often lies between 1 and 3 nm, and the narrow particle size distribution, are required to prepare efficient catalytic systems .
In this paper, we report the formation of Pd-containing nanoparticulate catalysts based on HPS as a support and Pd acetate as a Pd precursor in the direct catalytic oxidation of D-glucose to D-gluconic acid (Scheme 1).
This reaction is of both fundamental and technological importance . D-gluconic acid and its Ca salt are used in industry for pharmaceuticals and food supplement production. D-glucose oxidation is carried out in water, which makes it especially appealing for environmentally friendly catalysis. This reaction has been formerly performed over gold metal catalysts deposited on activated carbon, in the presence of O2  or with Au/Al2O3 using H2O2 as an oxidizing agent . Onal et al., reported that the selectivity of the target product varied from 80 to 95% . Moreover, when the concentration increased from 300 to 500 mmol/l, the selectivity was only 80%–85%. Saliger et al. reported that oxidation with H2O2 also resulted in low selectivity (75%–85%) .
The D-glucose catalytic oxidation is normally carried out in neutral or low-alkali media and the selectivity may be increased by addition of modifying agents . However, the resultant selectivity decreases at high rates of D-glucose conversion . Hence, the development of novel catalysts for D-glucose oxidation possessing higher activity, selectivity, and stability, is an important endeavor.
In our preceding paper, we reported on the behavior of Ru-containing HPS catalysts in D-glucose oxidation . The Ru catalysts developed displayed high activity and selectivity, however, the incorporation of Ru compounds in HPS required a three-step procedure. After impregnation of HPS, the Ru precursor was treated with an alkaline solution at 70°C for 3 h, then with a concentrated solution of H2O2 in the same conditions and then again with the alkaline solution, thus making the catalyst preparation time- and energy-consuming and environmentally unfavorable. In the present paper, incorporation of Pd acetate in HPS was carried out in one step by simple impregnation, while reduction to mixed oxidation state Pd nanoparticles was performed at room temperature. The catalysts developed were characterized using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen physisorption and were studied in D-glucose oxidation by oxygen. These catalysts demonstrated high selectivity and stability, along with reasonable activity, which makes them promising for industrial applications in sustainable processes.
2 Materials and methods
HPS was purchased from Moscow office of Purolite Int. (UK), as Macronet MN 270/3860 type 2/100 (designated as MN-270). The size of the MN-270 granules is 50–70 μm. The granules were washed with acetone and water twice and dried under vacuum for 24 h. Pd acetate [Pd(CH3COO)2], reagent-grade chloroform, acetone, D-gluconic acid and D-glucose were purchased from Aldrich (USA and Germany) and were used as received. Distilled water was purified with the Elsi-Aqua (ELSICO Ltd., Moscow) water purification system.
2.2 Catalysts synthesis
HPS (0.15 g) was impregnated with 0.006 g of Pd acetate dissolved in 1 ml of chloroform. After impregnation, the sample was dried in a vacuum oven at room temperature for 24 h to remove the solvent. Reduction with hydrogen gas was carried out at room temperature and normal pressure for 3 h.
X-ray fluorescence (XRF) measurements to determine the Pd content were performed with a Zeiss Jena VRA-30 spectrometer (Mo anode, LiF crystal analyzer and SZ detector). Analyses were based on the Co Kα line and a series of standards prepared by mixing 1 g of polystyrene with 10–20 mg of standard compounds. The time of data acquisition was constant at 10 s.
Nitrogen physisorption was conducted at the normal boiling point of liquid nitrogen, using a Beckman Coulter SA 3100 apparatus (Coulter Corporation, Miami, FL, USA). Samples were degassed in a Beckman Coulter SA-PREP apparatus for sample preparation (Coulter Corporation), at 120°C in a vacuum for 1 h, prior to the analysis.
X-ray photoelectron spectra were obtained using Mg Kα (hν=1253.6 eV) radiation with an ES-2403 spectrometer (provided by the Institute for Analytic Instrumentation of the Russian Academy of Sciences, St. Petersburg, Russia) equipped with energy analyzer PHOIBOS 100-MCD5 (SPECS, Germany). All data were acquired at an X-ray power of 100 W. Survey spectra were recorded at a step of 0.5 eV with analyzer pass energy 40 eV, and high resolution spectra were recorded at a step of 0.05 eV with analyzer pass energy 7 eV. Samples were allowed to outgas for 60 min before analysis and were sufficiently stable during examination.
TEM was performed with a JEOL JEM1010 transmission electron microscope operated at an accelerating voltage of 80 kV. Pd-containing HPS powders were embedded in epoxy resin and subsequently microtomed at ambient temperature. Images of the resulting thin sections (ca. 50 nm thick) were collected with the Gatan digital camera (Warrendale, USA) and analyzed with the Adobe Photoshop software package (San Jose, CA, USA) and the ImageJ program (NIH, USA).
2.4 D-glucose oxidation methodology
The oxidation of D-glucose was conducted batchwise in a PARR 4200 apparatus, which provides independent control over parameters such as D-glucose and NaHCO3 concentrations, catalyst concentration, temperature, (pure) oxygen feed rate, oxygen pressure and stirring rate. A suspension of the catalyst and an aqueous solution of D-glucose (20 ml), prepared at a predetermined concentration, were placed in the reactor. The rate of oxygen feed was controlled by a rotameter. The equimolar quantity of the alkalizing agent (NaHCO3) was fed to the apparatus continuously (to maintain pH in the range 6.0–7.5), using an automatic dispenser. The high stirring rates employed here ensured good mixing, without diffusion limitation. Samples of the reaction mixture were periodically removed for analysis. At the end of each experiment, the catalyst was separated by filtration and the filtrate was analyzed to measure, by HPLC, the content in D-glucose and in the sodium salt of D-gluconic acid.
HPLC analysis of the reaction products was provided using the Ultimate 3000 HPLC chromatograph (Dionex, USA), equipped with an RI detector, stainless steel column 250 mm×2 mm (Sapelcogel™-Ca, Sigma-Aldrich, Germany), characterized by 64,000 theoretical plates number. A phosphate buffer of pH 7.6 with a space velocity of 0.5 ml/min, at 50°C, was used as a mobile phase. The concentration of the sodium salt of D-gluconic acid and D-glucose varied from 0.001 to 10 mg/ml and the internal standard Xylite concentration was 1 mg/ml.
3 Results and discussion
3.1 Formation of Pd acetate nanoparticles in HPS and the nanocomposite structure
In our preceding paper , we studied Pd compound NP formation in the pores of HPS, depending on the hydrophobicity-hydrophilicity balance of the Pd compounds including (CH3CN)2PdCl2, (PhCN)2PdCl2, (Sty)(CH3CN)PdCl2, and (StyPdCl2)2. An increase of hydrophobicity of a Pd compound allowed for smaller NP formation, until hydrophobicity became too high, leading to spreading the Pd compound without NP formation. The highest catalytic activity was observed for the catalysts with the smallest NPs formed. In this paper, we used the commercially available and comparatively inexpensive Pd acetate as a precursor for formation of Pd compounds and Pd metal NPs. Figure 1 A shows TEM images of HPS filled with Pd acetate, with a Pd content of 3.09 wt%.
Despite the seemingly low hydrophobicity of Pd(CH3COO)2 compared to that of (PhCN)2PdCl2 or (Sty)(CH3CN)PdCl2, the Pd(CH3COO)2 incorporation leads to small NPs with a mean diameter of 3.6 nm and a standard deviation of 24%. It is noteworthy that Pd acetate forms tetramers or trimers, as presented in Figure 2, which increase the hydrophobicity of this compound and influence the compatibility with HPS.
Comparison of the pore volume distributions of HPS and HPS-PdAc-3.09 (Figure 3) demonstrates that the pore volume decreases from 0.8483 ml/g to 0.6759 ml/g upon incorporation of Pd acetate. This occurs mainly due to filling the 4 nm pores, while the fraction of 5 nm increases due to partial filling of larger pores. This is accompanied by the decrease of the Brunauer-Emmett-Teller (BET) surface area from 1504 m2/g to 1218 m2/g, which is consistent with a decrease of the amount of smaller pores.
Remarkably, the reduction of the dry HPS sample containing Pd(CH3COO)2 within its pores, with hydrogen gas, results in even smaller NPs of 2.2 nm diameter and standard deviation of 27%. This indicates that reduction occurs inside the pores, without a mass transfer between them, while the size decrease is consistent with the density increase from Pd(CH3COO)2 to Pd metal. A similar phenomenon was observed for fully microporous HPS, where mass transfer between pores was slow due to their small size . The HPS sample used in this work consists of micropores, small and large mesopores as indicated earlier , but apparently the presence of large mesopores does not jeopardize the control over Pd NP formation.
High resolution XPS Pd spectra of HPS-PdAc-3.09 and HPS-PdAc-H2-2.59 are presented in Figure 4. The shift of the spectrum towards lower binding energies in HPS-PdAc-H2-2.59 indicates the presence of more reduced species. Figure 5 presents deconvolution of both spectra.
The XPS spectrum of HPS-PdAc-3.09 is deconvoluted to two components, with the Pd 3d5/2 binding energies of 338.3 eV and 336.4 eV which we assign to Pd(CH3COO)2 (59.3%) and Pd(0), respectively. The shift of a binding energy of Pd(0) to higher values by ~1.5 eV compared to bulk values, is attributed to an NP size effect on final-state relaxation, because of charge screening in XPS, as reported by Penner et al. . This indicates that partial decomposition/reduction of Pd(CH3COO)2 occurs in HPS upon impregnation. According to deconvolution of the HPS-PdAc-H2-2.59 spectrum, reduction of HPS-PdAc-3.09 with hydrogen gas leading to HPS-PdAc-H2-2.59, also results in two components with binding energies 336.7 eV and 338.0 eV, which can be assigned to Pd and PdO , with a molar ratio of 1.0:1.1. Although reduction was carried out with hydrogen, surface oxidation of Pd NPs easily occurs under air .
3.2 Catalytic properties in D-glucose oxidation
The dependences of D-gluconic acid formation on time for the above catalysts are presented in Figure 6. For the HPS-PdAc-3.09 sample, one can see the part of the curve when D-glucose is consumed, but D-gluconic acid is not detected. This stage of the reaction is referred to as the induction period. Normally, the induction period is the period of time when catalytically active sites are formed. It can be very fast and nearly undetectable  or it can last for 1 h . In our case, the induction period lasts for 15 min, after which the target product starts accumulating. According to Agnelli et al., the complex reaction centers – “metal-support-substrate-solvent” – are formed during the induction period . To assess the changes occurring to the catalyst after the induction period and at the end of the reaction, we isolated catalysts after those points and designated them as HPS-PdAc-3.09-INDUCTION and HPS-PdAc-3.09-AFTER, respectively (Figure 7).
One can see minor aggregation of NPs due to diffusion facilitated in a liquid medium, while the NP size is largely preserved. The mean NP diameter of HPS-PdAc-3.09-INDUCTION is 3.5 nm and the standard deviation is 29%, while at the end of the reaction, the larger fraction of smaller particles is formed. The mean NP diameter for HPS-PdAc-3.09-AFTER is 2.4 nm and the standard deviation is 43%.
In the case of the HPS catalyst after reduction, HPS-PdAc-H2-2.59, the induction period was not observed, so we only collected the sample after the catalytic reaction (Figure 8). The TEM image shows NPs of 2.4 nm in diameter (24% standard deviation), indicating that NP size or morphology does not change after the catalytic reaction. It is worth noting that no aggregation was observed for this sample.
The catalytic data of HPS-PdAc-2.59-H2 in D-glucose oxidation (Table 1) show the increased activity, indicating that the NPs formed after hydrogenation, are more active.
Earlier, we demonstrated that the decrease of the amount of a catalytic metal can result in enhanced activity due to eliminating the overlap between NPs, which may lead to shielding of some catalytic sites from participating in the reaction . Following this, we synthesized the analogous catalyst containing less Pd and reduced it with H2 (Figure 9). This sample is designated HPS-PdAc-H2-1.09 (1.09 wt% Pd). Here, the mean NP diameter is 1.7 nm with a standard deviation of 24%.
The data presented in Figure 6 and Table 1 demonstrate that this catalyst possesses higher activity than the catalyst with 2.59 wt% Pd and the same selectivity, presumably due to smaller Pd NPs formed at lower Pd loading. We also carried out stability studies recovering the catalyst after the reaction using filtration (Table 1). These data demonstrate exceptional stability of the catalyst performance.
To understand the cause of the activity increase, we studied a temperature dependence of activity and determined the activation energy for each catalytic system. Figure 10 shows that the reaction temperature has a strong effect on the catalyst activity for all catalysts studied.
The values of apparent activation energy (Ea) and pre-exponential factor (k0) estimated for the three catalysts, are given in Table 2.
The data in Table 2 show that the pre-exponential factor, which is responsible for the amount of active centers, is nearly the same for all three catalysts. On the other hand, the activation energy decreases after reduction and even further decreases for smaller Pd NPs.
In this paper, we demonstrated that the formation of well-defined Pd-containing NPs can be controlled in the pores of HPS. This nanocomposite can be used directly in D-glucose catalytic oxidation and then catalytic species form in situ. Alternatively, the catalytic NPs can be formed by hydrogen reduction of Pd acetate in the HPS pores. In the former case, direct D-glucose oxidation shows an induction period when catalytically active sites are formed, while in the latter case, no induction period is observed. This prefabricated catalyst shows a significantly higher catalytic activity, although selectivity drops. By contrast, the decrease of the Pd precursor loading allows higher activity and selectivity of the prefabricated NPs than in the case of a higher loading. We believe that this is due to smaller Pd/PdO NPs with lower activation energy of the catalytic reaction, which display higher catalytic activity at a selectivity of 99.6%. The same catalyst demonstrated excellent stability after five repeated runs, making it a promising candidate for industrial applications in sustainable processes.
The financial support of this work was provided in part by funding from the European Community’s Seventh Framework Programme [FP7/2007–2013] under grant agreement no. CP-IP 24095. The authors also thank the Ministry of Education and Science of the Russian Federation and the Russian Foundation for Basic Research.
Philippe M, Didillon B, Gilbert L. Green Chem. 2012, 14, 952–956.Google Scholar
Parthasarathy G, Hart R, Jamro E, Miner L. Clean Tech. Env. Polic. 2005, 7, 219–229.Google Scholar
Fendler JH, Tian Y. In Nanoparticles and Nanostructured Films, Fendler JH, Ed., Wiley-VCH: New York, 1998.Google Scholar
Wieckowski A, Savinova ER, Vayenas CG. Catalysis and Electrocatalysis at Nanoparticle Surfaces, Marcel Dekker, Inc.: New York, 2003.Google Scholar
Schmid G. In Nanoparticles: From Theory to Application, Wiley-VCH Verlag GmbH & Co.: Weinheim, 2004, pp. 434.Google Scholar
Somorjai GA, Contreras AM, Montano M, Rioux RM. Proc. Nat. Acad. Sci. 2006, 103, 10577–10583.Google Scholar
Astruc D, Lu F, Aranzaes JR. Angew. Chem. Int. Ed. 2005, 44, 7852–7872.Google Scholar
Mueller C, Nijkamp MG, Vogt D. Eur. J. Inorg. Chem. 2005, 20, 4011–4021.Google Scholar
Bronstein LM. In Encyclopedia of Nanoscience and Nanotechnology, Nalwa HS, Ed., American Scientific Publishers: Los Angeles, 2004, pp. 193–206.Google Scholar
Antonietti M, Henz S. Nachr. Chem: Technol. Lab. 1992, 40, 308–314.Google Scholar
Antonietti M, Wenz E, Bronstein L, Seregina M. Adv. Mater. 1995, 7, 1000–1005.Google Scholar
Spatz JP, Roescher A, Möller M. Adv. Mater. 1996, 8, 337–340.Google Scholar
Moffitt M, McMahon L, Pessel V, Eisenberg A. Chem. Mater. 1995, 7, 1185–1192.Google Scholar
Saito R, Okamura S, Ishizu K. Polymer 1993, 34, 1189–1195.Google Scholar
Zhao M, Crooks RM. Angew. Chem. Int. Ed. 1999, 38, 364.Google Scholar
Shifrina ZB, Rajadurai MS, Firsova NV, Bronstein LM, Huang X, Rusanov AL, Muellen K. Macromolecules 2005, 38, 9920–9932.Google Scholar
Caruso F, Susha AS, Giersig M, Mohwald H. Adv. Mater. 1999, 11, 950–953.Google Scholar
Sidorov SN, Volkov IV, Davankov VA, Tsyurupa MP, Valetsky PM, Bronstein LM, Karlinsey R, Zwanziger JW, Matveeva VG, Sulman EM, Lakina NV, Wilder EA, Spontak RJ. J. Amer. Chem. Soc. 2001, 123, 10502–10510.Google Scholar
Sidorov SN, Bronstein LM, Davankov VA, Tsyurupa MP, Solodovnikov SP, Valetsky PM, Wilder EA, Spontak RJ. Chem. Mater. 1999, 11, 3210–3215.Google Scholar
Davankov VA, Tsyurupa MP. React. Polym. 1990, 13, 27.Google Scholar
Tsyurupa MP, Davankov VA. J. Polym. Sci.: Polym. Chem. Ed. 1980, 18, 1399.Google Scholar
Rampino LD, Nord FF. J. Am. Chem. Soc. 1941, 63, 2745.Google Scholar
Bronstein LM, Goerigk G, Kostylev M, Pink M, Khotina IA, Valetsky PM, Matveeva VG, Sulman EM, Sulman MG, Bykov AV, Lakina NV, Spontak RJ. J. Phys. Chem. B 2004, 108, 18234–18242.Google Scholar
Bronstein L, Goerigk G, Kostylev M, Pink M, Khotina IA, Valetsky PM, Matveeva VG, Sulman EM, Sulman MG, Bykov AV, Lakina NV, Spontak RJ. J. Phys. Chem. B 2004, 108, 18234–18242.Google Scholar
Sulman E, Doluda V, Dzwigaj S, Marceau E, Kustov L, Tkachenko O, Bykov A, Matveeva V, Sulman M, Lakina N. J. Molec. Catal. A 2007, 278, 112–119.Google Scholar
Bykov A, Matveeva V, Sulman M, Valetskiy P, Tkachenko O, Kustov L, Bronstein L, Sulman E. Catal. Today 2009, 140, 64–69.Google Scholar
Roldan Cuenya B, Baeck S-H, Jaramillo TF, McFarland EW. J. Am. Chem. Soc. 2003, 125, 12928–12934.Google Scholar
Nowakowski P, Dallas J-P, Villain S, Kopia A, Gavarri J-R. J. Solid. State Chem. 2008, 181, 1005–1016.Google Scholar
Kokoh KB, Leger JM, Beden B, Lamy C. Electrochim. Acta 1992, 37, 1333–1342.Google Scholar
Onal Y, Schimpf S, Claus P. J. Catal. 2004, 223, 122–133.Google Scholar
Saliger R, Decker N, Pruesse U. Appl. Catal. B: Environ. 2011, 102, 584–589.Google Scholar
Besson M, Gallezot P. In Fine Chemicals through Heterogeneous Catalysis, Sheldon RA, Van Bekkum H, Eds., Wiley–VCH: Weinheim, 2001, pp. 491–506.Google Scholar
Tsvetkova IB, Matveeva VG, Doluda VY, Bykov AV, Sidorov AI, Schennikov SV, Sulman MG, Valetsky PM, Stein BD, Chen C-H, Sulman EM, Bronstein LM. J. Mater. Chem. 2012, 22, 6441–6448.Google Scholar
http://www.ccdc.cam.ac.uk/products/csd/. Accessed on 18 October 2012.
Penner S, Bera P, Pedersen S, Ngo LT, Harris JJW, Campbell CT. J. Phys. Chem. B 2006, 110, 24577–24584.Google Scholar
Lee C-L, Chiou H-P. Appl. Catal. B: Environ. 2012, 117–118, 204–211.Google Scholar
Matveeva V, Bykov A, Doluda V, Sulman M, Kumar N, Dzwigaj S, Marceau E, Kustov L, Tkachenko O, Sulman E. Top. Cat. 2009, 52, 387–393.Google Scholar
Agnelli M, Swaan HM, Marquezalvarez C, Martin GA, Mirodatos C. J. Catal. 1998, 175, 117.Google Scholar
Sulman EM, Matveeva VG, Doluda VY, Sidorov AI, Lakina NV, Bykov AV, Sulman MG, Valetsky PM, Kustov LM, Tkachenko OP, Stein BD, Bronstein LM. Appl. Catal. B: Environ. 2010, 94, 200–210.Google Scholar
About the article
Valentin Y. Doluda
Valentin Yu. Doluda is a scientist at the Department of Biotechnology and Chemistry of Tver Technical University (Tver, Russia). He received his MS degree cum laude from Tver Technical University and his PhD in Physical Chemistry from Ivanovo University of Chemistry and Technology (Ivanovo, Russia). He started his research and educational career at Tver Technical University, first as a junior researcher, then as a research associate, a senior scientist, and as a leading scientist starting from 2001. During his research career, he published more than 38 papers, reviews and book chapters. Valentin Doluda’s research program focuses on developing new catalysts for fine organic synthesis and energy application.
Irina B. Tsvetkova
Irina B. Tsvetkova is an Assistant Scientist at the Department of Chemistry, Indiana University. She received her MS degree from D.I. Mendeleev Russian University of Chemical Technology (Moscow, Russia) and her PhD in Polymer Chemistry from the A.N. Nesmeyanov Institute of Organoelement Compounds (INEOS) of the Russian Academy of Sciences (Moscow, Russia). She started her research career at INEOS, first as a junior researcher, and then she moved to Indiana University as a postdoctoral associate. Dr. Tsvetkova’s research is focused on the study of the fundamentals of nanoparticle-templated protein assembly, as well as synthesis of metal nanoparticles in polymeric systems.
Alexey V. Bykov
Alexey V. Bykov is an associate professor of the Department of Biotechnology and Chemistry, Tver Technical University, Tver, Russian Federation. He received his diploma (Chemistry) cum laude of Tver Technical University (Tver, Russia) in 2002 and his PhD in physical chemistry and catalysis from Ivanovo University of Chemistry and Technology (Ivanovo, Russia) in 2007. He started his research career in Tver Technical University as an engineer and then as an associate professor from 2009. He has published more than 23 papers and reviews. He is interested in catalysis, physics and chemistry of surface and nanosystems.
Valentina G. Matveeva
Valentina G. Matveeva is a Professor at the Department of Biotechnology and Chemistry of Tver Technical University (Tver, Russia) and Director of Analytical Laboratory of the Institute of Nano- and Biotechnologies. She graduated from Tver Technical University in 1986. She received her PhD in 1995 and became a full professor at Tver University in 2001. She started her career in Tver Technical University, first as a research associate, then as an associate professor and professor from 2002 at Tver Technical University. She has published more than 85 papers, reviews and book chapters. Her research interests are catalysis, energy conservation and life sciences.
Alexander I. Sidorov
Alexander I. Sidorov is a Professor at the Department of Biotechnology and Chemistry Tver Technical University. He graduated from Tver Technical University in 1982 and received his PhD at the Institute of Organic Chemistry, Russian Academy of Sciences (Moscow, Russia) in 1995. He started his research career in 1985 as a research associate, then as an associate professor and as a professor from 2008 at Tver Technical University. He has published more than 43 papers, reviews and book chapters. His research interests are catalysis, biotechnology and life sciences.
Mikhail G. Sulman
Michael G. Sulman is a Professor of the Department of Automation of Technological Processes, deputy vice-rector at Tver Technical University (Tver, Russia) and Head of Laboratory of Polymer Synthesis at the A.N. Nesmeyanov Institute of Organoelement Compounds (INEOS) of Russian Academy of Sciences (Moscow, Russia). In 1990, he graduated cum laude from Tver Technical University, and in 1994 he received his PhD at Tver Technical University and became a full professor at Tver University in 2001. He started his research career in Tver Technical University, first as an assistant professor in 1990, then as an associate professor and professor at Tver Technical University. He has published more than 43 papers, reviews and book chapters. His research interests are catalysis, energy conservation and mathematical modeling.
Pyotr M. Valetsky
Pyotr M. Valetsky is a leading scientist in the Group of Polymer Synthesis of the A.N. Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences. He received his MS degree cum laude from the D. I. Mendeleyev University of Chemical Technology (Moscow, Russia) and his PhD in Polymer Chemistry from the A.N. Nesmeyanov Institute of Organoelement Compounds. He has published more than 350 papers and reviews, and has received more than 100 Russian and international patents. Dr. Valetsky’s research program focuses on developing new nanocomposites based on various kinds of polymers for catalytic, bactericidal and construction applications.
Barry D. Stein
Barry D. Stein is an Assistant Research Scientist at the Indiana Molecular Biology Institute (IMBI) at Indiana University in Bloomington. He received his BS and MS degrees from the Biology Department at Northeastern University in Boston, Massachusetts and his PhD from the Biology and Plant Pathology Department at Michigan State University in Lansing. His PhD research was on the ultrastructure of lignification and mineralization in cucumber plants, which occurs as a response to fungal infection. As a research associate at Tufts University, he used microscopy to examine infection of host cells by the enteric parasite Cryptosporidium. He is a co-author on 62 publications and has been the manager of the microscopy facility at IMBI since 2000.
Esther M. Sulman
Esther M. Sulman is a Director of the Institute of Nano- and Biotechnologies and Head of the Department of Biotechnology and Chemistry of Tver Technical University (Tver Russia). She received her MS degree cum laude from Tver Technical University, her PhD at the Institute of Organic Catalysis and Electrochemistry (Kazakhstan) in 1972 and became a full professor at the Institute of Organic Chemistry, Russian Academy of Sciences (Moscow, Russia) in 1989. She started her research career in Tver Technical University, first as a research associate, then as an assistant professor and professor since 1968. She has published more than 120 papers, reviews and book chapters and has more than 40 patents of Russian Federation. Her research interests are catalysis, renewable energy sources, biotechnology and life sciences.
Lyudmila M. Bronstein
Lyudmila M. Bronstein is a Senior Scientist at the Department of Chemistry, Indiana University, and an Adjunct Distinguished Professor at King Abdulaziz University, Jeddah, Saudi Arabia. She received her MS degree cum laude from Tver Technical University (Tver, Russia) and her PhD in polymer chemistry from the A.N. Nesmeyanov Institute of Organoelement Compounds (INEOS) of Russian Academy of Sciences (Moscow, Russia). She started her research career at INEOS first as a junior researcher, then a research associate, a senior scientist, and as a leading scientist starting from 1997. In 1999 she moved to Indiana University. During her research career, she published more than 170 papers, reviews, and book chapters. Dr. Bronstein’s research program focuses on developing new materials with important applications in the fields of energy, catalysis, and life sciences.
Published Online: 2013-02-02
Published in Print: 2013-02-01