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87 results on '"Smotkin, Eugene S."'

63. In-Site Polarization Modulated FTIR and Differential Electrochemical Mass Spectroscopy

Author

ILLINOIS INST OF TECH CHICAGO, Smotkin, Eugene S., ILLINOIS INST OF TECH CHICAGO, and Smotkin, Eugene S.

Abstract

We recently report the electrochemical promotion of the heterogeneously catalyzed isomerization of 1-butene to cis- and trans-butene with p values of 38 and 46, respectively. at the remarkably low temperature of 70 Deg C using Nafion as the electrolyte in a fuel cell configuration. This was the first reported case of a NEMCA promoted unimolecular and non-redox reaction concomitant with the reduction of butene to butane. We now present isotopic mass spectral and FTIR data confirming the mechanism involves abstraction of a proton from the catalytic surface for Markovnikov addition to the C-I carbon concomitant with removal of a proton from C-3 to yield the isomer. This striking example of an acid catalyzed reaction at a metal surface is facilitated by the use of the super acidic Nafion electrolyte. Material: 1-butene: cis-2-butene; trans-2-butene; Nafion; Pd; Deuterium; D2O.

Published
2000

64. Direct Methanol Fuel Cell Development.

Author

ILLINOIS INST OF TECH CHICAGO, Smotkin, Eugene S., ILLINOIS INST OF TECH CHICAGO, and Smotkin, Eugene S.

Abstract

The focus of the first year of this two-year program was the development of an electrolyte system for fuel cells and other electrochemical reactors, which allows proton transfer through the electrolyte system but prevents crossover of lager chemical species from one electrode side to the other electrode side of the fuel cell. The first year effort of this program resulted in the filing of a U.S. patent application in Jan. 16, 1996 that was issued on Dec. 8, 1998 (United States Patent 5,846,669). The patent was based on work published in 1995 by Cong Pu, Wenhua Huang, K. L. Ley and E. S. Smotkin, "A Methanol Impermeable Proton Conducting Composite Electrolyte System," J. Electrochem. Soc., 142, L119-L120 (1995). This work was attributed to the DARPA grant. The second year of the program was focused on the development of new anodes for direct methanol fuel cells. This work resulted in a second patent entitled "Single Phase Ternary Pt-Ru-Os Catalysts for Direct Oxidation Fuel Cells" (United States Patent 5,856,036). Ley et al. based this patent on a publication, "Methanol Oxidation on single-Phase Pt-Ru-Os Ternary Alloys", "J. Electrochem. Soc., 144, 1543-1548 (1997). This work was attributed to the DARPA grant.

Published
1999

76. ARO Fuel Cell/Battery/Manufacturing HUB Program.

Author

ILLINOIS INST OF TECH CHICAGO DEPT OF CHEMISTRY, Smotkin, Eugene S., ILLINOIS INST OF TECH CHICAGO DEPT OF CHEMISTRY, and Smotkin, Eugene S.

Abstract

The fuel cell program has made progress in four key areas including (1) fabrication and testing of membrane electrode assemblies (MEAs), (2) fundamental studies of methanol oxidation on smooth alloy electrodes, (3) half cell studies of membrane electrode assemblies and (4) X-ray studies of anode catalytic materials. Two fuel cell test stands with computerized data acquisition systems are now fully operational. We have fabricated MEAs with hydrogen/oxygen performance curves competitive with state-of-the-art electrodes. In addition, studies of Pd barrier electrodes have been initiated and currents of 400 mA/sq cm at 0.5 volts are typical with hydrogen/methanol-oxygen. We have now terminated the hydrogen/methanol blend experiments and are now focusing on liquid methanol/water feed. We are currently struggling with the methanol delivery system and development of macroporous electrodes for methanol. Since the time of this report, IIT and Argonne National Laboratory have made one visit to the synchrotron at Brookhaven National Laboratory. Data analysis is in progress. jg

Published
1995

82. In situ x-ray absorption fuel cell.

Author

Viswanathan, Rameshkrishnan, Liu, Renxuan, and Smotkin, Eugene S.

Subjects
X-ray spectroscopy, POLYELECTROLYTES, FUEL cells, EQUIPMENT & supplies
Abstract

An in situ x-ray absorption spectroscopy cell was designed to study the structural and electronic properties of high performance polymer electrolyte fuel cell electrocatalysts. The cell was operated as a standard fuel cell and x-ray absorption data were collected simultaneously as the fuel cell operating conditions were varied. The cell was used to examine platinum-ruthenium alloy electrocatalysts incorporated in the anode of a fuel cell membrane and electrode assembly. In situ Pt L[sub III] and Ru K edge x-ray absorption near-edge structure (XANES) data were collected at five selected current densities of the operating fuel cell. The XANES data show that under normal fuel cell operating conditions, the metallic nature of the Pt-Ru catalyst is retained. The cell design enabled an in situ fuel cell study at a synchrotron source in which no additional electrolytes were required. [ABSTRACT FROM AUTHOR]

Published
2002
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83. Influence of Anions on Proton-Conducting Membranes Based on Neutralized Nafion 117, Triethylammonium Methanesulfonate, and Triethylammonium Perfluorobutanesulfonate. 2. Electrical Properties

Author

Di Noto, Vito, Piga, Matteo, Giffin, Guinevere A., Lavina, Sandra, Smotkin, Eugene S., Sanchez, Jean-Yves, and Iojoiu, Cristina

Abstract

The electrical properties of a Nafion proton exchange membrane change dramatically when neutralized and then doped with a proton-conducting ionic liquid (PCIL). Broadband electric spectroscopy elucidates the molecular relaxation and polarization phenomena of neutralized Nafion (nN117) doped with triethylammonium methanesulfonate (TMS) and triethylammonium perfluorobutanesulfonate (TPFBu) ionic liquids. These data, coupled with those of part 1 suggest proton conduction mechanisms for both the pure PCILs and in PCIL-doped nN117. At 130 °C, the PCILs have conductivities of σTMS= 1.4 × 10–2 S/cm and σTPFBu= 9 × 10–3 S/cm, while correspondingly doped nN117 have conductivities of σNTMS= 6.1 × 10–3S/cm and σNTPFBu= 1.8 × 10–3 S/cm. The pure PCILs show three interfacial polarizations associated with proton transfer mechanisms above the melting point. PCIL-doped nN117 also has three interfacial polarizations that depend on the nanostructure characteristics of the PCIL sorbed within the nN117 polar domains. Below the PCIL melting point, doped nN117 has two dielectric relaxations, α and β, associated with dipolar relaxations involving both the sorbed PCILs and the ionomer matrix. The data indicate a long-range charge transfer process that occurs through proton exchange between cationic clusters. Segmental motion of the polymer chains and the molecular dimensions of the ionic liquid nanoaggregates mediate this charge transfer.

Published
2012
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84. Influence of Anions on Proton-Conducting Membranes Based on Neutralized Nafion 117, Triethylammonium Methanesulfonate, and Triethylammonium Perfluorobutanesulfonate. 1. Synthesis and Properties

Author

Noto, Vito Di, Piga, Matteo, Giffin, Guinevere A., Lavina, Sandra, Smotkin, Eugene S., Sanchez, Jean-Yves, and Iojoiu, Cristina

Abstract

The effect of the anion structure of proton-conducting ionic liquid dopants on the properties of a Nafion 117 membrane, neutralized by triethylammonium, is described. The synthesis and the properties of proton-conducting membranes doped with triethylammonium methanesulfonate (TMS) or triethylammonium perfluorobutanesulfonate (TPFBu) ionic liquids are described. The properties of the doped membranes were investigated by thermogravimetric analysis, differential scanning calorimetry, and dynamic-mechanical analysis. The key findings are that the uptake of the ionic liquid is ca. 25 and 40 wt % for TMS and TPFBu, respectively, and these ionic liquid dopants extend the membranes thermal stability to 140 °C. Information concerning the structure and the interactions between the membrane components was obtained by Fourier transform infrared spectroscopy.

Published
2012
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85. Electrochemical Activation of Catalysis (Book).

Author

Smotkin, Eugene S.

Subjects
ELECTROCHEMICAL Activation of Catalysis (Book), VAYENAS, Costas, BEBELIS, Symeon, PLIANGOS, Costas
Abstract

Reviews the book 'Electrochemical Activation of Catalysis: Promotion, Electrochemical Promotion, and Metal Support Interactions,' by Costas Vayenas, Symeon Bebelis, Costas Pliangos, Susanne Brosda and Demetrios Tsiplakides.

Published
2002
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86. CO2 attraction by specifically adsorbed anions and subsequent accelerated electrochemical reduction

Author

Ogura, Kotaro, Ferrell, Jack R., Cugini, Anthony V., Smotkin, Eugene S., and Salazar-Villalpando, Maria D.

Subjects
*CHEMICAL reduction, *ELECTROCHEMISTRY, *HYDROGEN, *HIGH voltages, *HALIDES, *CHARGE exchange
Abstract

Abstract: The electrochemical reduction of CO2 was studied on a copper mesh electrode in aqueous solutions containing 3M solutions of KCl, KBr and KI as the electrolytes in a two and three phase configurations. Electrochemical experiments were carried out in a laboratory-made, divided H-type cell. The working electrode was a copper mesh, while the counter and reference electrodes were Pt wire and Ag/AgCl electrode, respectively. Results of our work suggest a reaction mechanism for the electrochemical reduction of CO2 in the two phase configuration where the presence of Cu-X as the catalytic layer facilitates the electron transfer from the electrode to CO2. Electron-transfer to CO2 may occur via the X ad −(Br−, Cl−, I−)–C bond, which is formed by the electron flow from the specifically adsorbed halide anion to the vacant orbital of CO2. The stronger the adsorption of the halide anion to the electrode, the more strongly CO2 is restrained, resulting in higher CO2 reduction current. Furthermore, it is suggested that specifically adsorbed halide anions could suppress the adsorption of protons, leading to a higher hydrogen overvoltage. These effects may synergistically mitigate the overpotential necessary for CO2 reduction, and thus increase the rate of electrochemical CO2 reduction. [Copyright &y& Elsevier]

Published
2010
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87. Activation of nanoparticle Pt-Ru fuel cell catalysts by heat treatment: a 195Pt NMR and electrochemical study.

Author

Babu PK, Kim HS, Kuk ST, Chung JH, Oldfield E, Wieckowski A, and Smotkin ES

Abstract

(195)Pt NMR spectroscopic and electrochemical measurements were carried out on commercial Pt-Ru alloy nanoparticle samples to investigate the effect of high-temperature annealing in different vacuum/gas-phase environments. Samples annealed at 220 degrees C in Ar gas, or in a vacuum, did not show any demonstrable change in catalytic activity vs electrochemically reduced, room-temperature samples. In contrast, annealing at 220 degrees C in H(2) gas led to a 3-fold increase in reactivity toward methanol oxidation (per surface site). NMR experiments show that annealing at 220 degrees C (in both Ar and H(2)) leads to a slight reduction in the Fermi level local density of states (E(F)-LDOS) at the Pt sites, which we attribute to surface enrichment of Ru. This electronic effect alone, however, appears to be too small to account for the increase in the catalytic activity observed for the H-treated catalyst. By comparing the electrochemical and NMR data of the H- and Ar-treated samples, we conclude that annealing at 220 degrees C in the hydrogen atmosphere reduces surface Ru oxides into metallic Ru, and consequently, the presence of metallic Ru and its enrichment on the surface are essential for the enhanced catalytic activity. In contrast, heat treatment at 600 degrees C in both vacuum and argon atmosphere increases the particle size and reduces the amount of platinum on the nanoparticle surface, thereby increasing the surface Ru content beyond the optimum surface composition values. This causes a large reduction in catalytic activity. Our results suggest that optimizing the amount of surface Ru by heat treatment at temperatures near 200 degrees C, in a hydrogen atmosphere, can be utilized to produce Pt-Ru alloy nanoparticles with high methanol oxidation activity. Finally, our NMR and electrochemical data, taken together with the lattice parameter measurements, lead to a novel model of Pt-Ru alloy nanoparticles having a Ru-rich core and a Pt-Ru alloy overlayer.

Published
2005
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