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Spherical micron-sized carbon powders were synthesized from feedstock furfuryl alcohol and tested as anodes in sodium ion batteries (SIBs). A long cycle life of 1000 cycles is achievable with this carbon at C rate (3–4 mg cm−2 loading and i = 200 mA g−1) yielding a steady capacity of ca. 115 mA h g−1. The results from solid-state 23Na MAS NMR analyses of cycled electrodes indicate no correlation in voltage profiles with sodium site nature (graphene or nanopores), which is a new observation in SIB carbon anodes.

The effect of boron substituted carbon (BC x , x ∼ 3–5) coatings on the hydrogen adsorption properties of porous carbons was investigated via spectroscopic characterization and hydrogen adsorption measurements. Thin films of BC x were synthesized by reacting BCl 3 and benzene in a chemical vapor and then depositing the product as a solid (CVD). The BC x deposits were collected on microporous carbon substrates and mesoporous silica aerogel. High-resolution solid-state boron NMR, 11 B HR-NMR, detected boron atoms in a symmetric chemical environment with trigonal coplanar coordination. Results from analyses based on NMR, X-ray photoelectron spectroscopy (XPS), and d-spacings, calculated from electron diffraction and X-ray diffraction (XRD) patterns, indicated that 17 at.% boron was substitutionally incorporated into the carbon framework. Thus the material has an empirical formula of BC 4.9 . Hydrogen adsorption data were collected at 100 bar and 25 °C. The BC x coatings reduced the surface area of the porous substrates by 30–50%. However, at the same time, they increased the heat of adsorption and the adsorption capacities per unit area by as much as a factor of five. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) revealed wagging energies at 1190 cm −1 attributable to hydrogen interactions with C–B–C bonds.

We present a simple method to synthesize shape selective carbon catalysts for large alkene hydrogenation reactions by tailoring porosity of platinum embedded in polyfurfuryl alcohol derived carbons. A small amount of mesoporosity, in addition to the intrinsic microporous nature of the carbon, shortens the diffusion length for the reactant molecule, enabling these materials to be used for catalysis in the liquid phase. A systematic study of hydrogenation reactions of liquid phase alkenes is reported. The molecular sieving effect of the catalyst was examined by varying molecular length, size, double bond position, stereoregularity and the number of double bonds in the alkenes.

(2012). A New Approach to Intellectual Property Management and Industrially Funded Research at Penn State. Research-Technology Management: Vol. 55, No. 5, pp. 12-17.

The Greater Philadelphia Innovation Cluster (GPIC) for Energy-Efficient Buildings is breaking new ground on how public-private research partnerships are conducted. A consortium of public, private, ...

Asymmetric aqueous electrochemical capacitors with energy densities as high as 22 Wh kg −1 , power densities of 11 kW kg −1 and a cell voltage of 2 V were fabricated using cost effective, high surface carbon derived from coal tar pitch and manganese dioxide. The narrow pore size distribution of the activated carbon (mean pore size ∼0.8 nm) resulted in strong electroadsorption of protons making them suitable for use as negative electrodes. Amorphous manganese dioxide anodes were synthesized by chemical precipitation method with high specific capacitance (300 F g −1 ) in aqueous electrolytes containing bivalent cations. The fabricated capacitors demonstrated excellent cyclability with no signs of capacitance fading even after 1000 cycles.

Porous solids are of great technological importance due to their ability to interact with gases and liquids not only at the surface, but throughout their bulk. Although large pores can be produced and well controlled in a variety of materials, nanopores in the range of 2 nm and below (micropores, according to IUPAC classification) are usually achieved only in carbons or zeolites. To date, major efforts in the field of porous materials have been directed towards control of the size, shape and uniformity of the pores. Here we demonstrate that porosity of carbide-derived carbons (CDCs) can be tuned with subångström accuracy in a wide range by controlling the chlorination temperature. CDC produced from Ti3SiC2 has a narrower pore-size distribution than single-wall carbon nanotubes or activated carbons; its pore-size distribution is comparable to that of zeolites. CDCs are produced at temperatures from 200-1,200 degrees C as a powder, a coating, a membrane or parts with near-final shapes, with or without mesopores. They can find applications in molecular sieves, gas storage, catalysts, adsorbents, battery electrodes, supercapacitors, water/air filters and medical devices.

A novel method for producing carbon membranes for ultrafiltration applications is presented using a spray deposition and pyrolysis of poly(furfuryl alcohol)/poly(ethylene glycol) mixtures on macroporous stainless steel supports. The poly(ethylene glycol) or PEG employed as a carbonization template creates a mesoporosity that leads to pores in the ultrafiltration range. Scanning electron microscopy (SEM) shows that the membranes consisted of 12- to 15-m thick carbon films. Gas permeation and water permeability data were used for the calculation of mean pore sizes, which were found to decrease with decreasing average molecular weight of the PEG template. Ultrafiltration of a polydisperse dextran solution was used to quantify the retention properties of the membranes. Molecular weight cutoffs determined from dextran retention data were shown to vary with template molecular weight: values of 2 × 10 4 ,3 .5 × 10 4 , and 6 × 10 4 gm ol −1 dextran were measured for respective templates of 2000, 3400, and 8000 g mol −1 PEG. For PEG molecular weights of 2000 or below, the templating effect was ill defined, membrane film cracking became more prominent, and membrane selectivity and reproducibility were adversely affected. © 2002 Published by Elsevier Science B.V.

New preparation techniques for synthesis of thin film supported nanoporous carbon membranes (SNPCM) using ultrasonic deposition (UD) have been examined. In contrast to other work we have published, in which membranes were prepared either by brush or spray coating of the polymer precursor onto the porous stainless steel support, the ultrasonic deposition method provides a greater degree of control over the deposition step. Permeation experiments on the UD-SNPCM with pure gases such as nitrogen (N 2 ) and oxygen (O 2 ) were used to benchmark properties and characteristics as a function of synthesis variables. The UD-SNPCM display ideal separation factors for O 2 /N 2 ranging from 2 to 30 depending on synthesis conditions. With other gases ideal separation factors were as large as: H 2 /CH 4 =600, CO 2 /CH 4 =45, N 2 O/N 2 =17, and H 2 /CO 2 =14 at 295 K. Permeation rates ranged from 7.9×10 −13 to 4.1×10 −8 mol m −2 Pa −1 s −1 and were largely independent of pressure. Oxygen versus nitrogen selectivities were inversely proportional to oxygen flux.

Nanoporous carbons (NPC) can be fabricated in the form of supported thin films with minimal defects and remarkably high size selectivity of oxygen over nitrogen. Spray coating of porous stainless steel disks with a solution of poly(furfuryl) alcohol (PFA) in acetone was used to synthesize nanoporous carbon membranes in a reproducible manner, and is the first reported case of this technique being used for supported carbon membrane synthesis. The disks were dried and then pyrolyzed in an inert atmosphere to a final temperature of 600°C. The resulting membranes were tested with binary oxygen/nitrogen mixtures. In experiments with a binary feed of oxygen and nitrogen, the membranes were found to have good oxygen over nitrogen selectivities (up to 4) and O 2 fluxes on the order of 10 −9 mol/m 2 s Pa. Attempts were made to modify membrane performance further by post-pyrolysis heating, additional coatings or by hydrocarbon pyrolysis. None of these post-treatments produced membranes superior to those derived directly from the initial spray coating and pyrolysis.

Carbon monoxide hydrogenation studies on silica- and alumina-supported Rh catalysts conducted in our laboratories as well as those reported in the literature suggest that the addition of early transition-metal oxides to the catalyst surface exerts a promotional influence on active Rh centers. This promotion leads to enhanced oxygenate selectivity. Explanations of the promotional influence of the early transition-metal oxides fall into three categories: (i) kinetic stabilization of small Rh aggregates, (ii) wetting and spreading of the transition-metal oxide, leading to decoration of the surface of Rh crystallites, and (iii) oxidative stabilization of Rh aggregates, altering Rh interactions with sub-carbonyls during reaction. Characterization of the RhMo γ- Al 2 O 3 system provides supporting evidence for both kinetic stabilization and oxidative stabilization of Rh aggregates and suggests that these processes contribute to the enhanced oxygenate selectivity of these materials. Hydrogen and carbon monoxide chemisorption results provide evidence for highly dispersed and oxidatively stabilized Rh aggregates. Even after extended on-stream testing (> 10 h), where metal aggregation is unavoidable, high-resolution transmission electron microscopy, associated energy dispersive spectroscopy, and the use of fast-Fourier transform post-processing to produce optical diffractograms highlight differences in the metal-aggregate morphology.

This study highlights the nature of the interactions between the transition metals in the Rh-Mo/γ-Al2O3 system and the underlying alumina surface. The investigation was carried out in the context of exploring the retrograde dehydration to dimethyl ether of primary alcohols produced at active metal sites during CO hydrogenation. Both native γ-Al2O3 and Rh-Mo/γ-Al2O3 samples were doped with KNO3 in an attempt to create an alkaline-metal oxide layer on the support surface which would screen alcohols from underlying Lewis acidity. The samples were characterized by microreactor-based methanol dehydration studies, analysis of infrared spectra of adsorbed pyridine, and ammonia saturation and temperature-programmed desorption. As expected, the dehydration activity of the samples was strongly correlated to their potassium loading and, hence, their Lewis acidity. More intriguing, however, are the insights gained in this analysis concerning the nature of the interactions between Mo, Rh, and the Lewis acid sites on the alumina surface. Our results are consistent with the principle, suggested in the Mo/γ-Al2O3 literature, that our Mo(CO)6 precursor interacts primarily with nonacidic hydroxyl groups on the dehydrated alumina surface. Furthermore, we provide strong evidence for the diminution of acidity brought on by the adsorption of Rh on Lewis acid sites of Mo/γ-Al2O3.

Catalytic membrane reactors are of particular interest for reactions that are severely thermodynamically limited. A case study is developed comparing and contrasting cyclohexane dehydrogenation with isobutane dehydrogenation in a palladium membrane reactor. The former is an often chosen model dehydrogenation, while the latter is of high, current industrial interest. Based on the literature and modeling it is concluded that cyclohexane dehydrogenation accentuates the effect of the membrane on supra-equilibrium conversion. More favorable thermodynamics, stoichiometry and kinetics for cyclohexane versus isobutane dehydrogenation each contribute. To achieve similar levels of membrane-assisted conversion, the reactor volume required for isobutane dehydrogenation would need to be at least 750 times larger than that required for cyclohexane based upon published kinetics for commercial catalysts. Rate limitations at the catalyst rather than for hydrogen transport through the membrane tend to dominate. The hydrogen deficiency in the reaction zone resulting from the membrane transport also leads to enhanced rates of coke formation resulting in catalyst and membrane deactivation. This study points out that more effort needs to be expended on the development of new dehydrogenation catalysts with high activity per unit volume and high resistance to deactivation.

A comparison is made between the activities and selectivities of several native manganese oxides (MnO, Mn 3 O 4 , Mn 2 O 3 , MnO 2 , Cu-MnO 2 ) for carbon monoxide reduction. At 310°C, and 500 psi on feeding synthesis gas (CO/H 2 =1/1), the carbon monoxide conversion levels are comparable but selectivities are quite different. Mn 2 O 3 displays over 90% selectivity for methanol while MnO displays less than 10% selectivity for methanol but over 50% selectivity for carbon dioxide. Patterns of activity and selectivity are discussed for each of the precursors. Interestingly, despite the quite varied selectivities at comparable conversion levels, X-ray diffraction on the used catalysts indicates that each has been converted to MnO in the bulk as would be expected from thermodynamics.

The reaction pathways, kinetics and mechanisms of 4-(naphthylmethyl)bibenzyl (NBBM) have been studied in order to resolve the fundamentals underlying the catalysis of coal liquefaction by Fe-based catalysts. Reactions of NBBM: ( 1 ) under nitrogen in the absence of catalyst, (2) under hydrogen in the absence of catalyst, (3) under nitrogen in the presence of the catalyst precursor Fe(CO) 3 (PPh 3 ) 2 , and (4) under hydrogen in the presence of the catalyst precursor Fe(CO) 3 (PPh 3 ) 2 were accomplished. Thermolysis was selective for cleavage of the weak bibenzyl bond, whereas the catalyst precursor effected cleavage at the naphthyl moiety. The catalyst precursor was most effective in the presence of hydrogen, where the rate of consumption of NBBM and the selectivity of breaking the bond at the naphthalene ring both increased. Hydrogenation activity was also observed. Possible mechanisms are proposed to describe the pyrolytic and catalytic reactions of NBBM.

Product shape selective effects, to date observed only with zeolites and a few other crystalline molecular sieves, should be generalizable and thus useful in the design of other novel catalyst materials. To be a viable approach in general for a given reaction, the only requirement for product shape selectivity is that the molecules involved be sufficiently different in size that they transport through micropore structures at different rates. Here, it is reported for the first time that non-crystalline composite catalysts, consisting of silica-alumina and amorphous carbogenic molecular sieves, are able to produce mono- and dimethylamines from methanol and ammonia with higher selectivities than the silica-alumina catalyst, currently used in the commercial practice. With the standard catalyst at ∼ 85% methanol conversion a ratio of (MMA + DMA)/TMA = 1 results, while the new catalyst, designated CMS-SiO 2 -Al 2 O 3 , at the same conditions and methanol conversion, produces ratios of at least (MMA + DMA)/TMA = 2.7. Although the rate of conversion per gram on the new catalyst is only one-third that of the standard catalyst, this is more than adequate activity for a commercial fixed-bed process. A model that accounts for reaction on silica-alumina and diffusion in the molecular sieve carbon is described. By adjusting the diffusivities of the three amines good agreement between prediction and experiment is obtained.

Alumina supported rhodium and rhodium-molybdenum catalysts, prepared by non-aqueous, sequential chemisorption, are compared for CO hydrogenation. The catalysts are also characterized by in situ FTIR. The observed significant increase in CO hydrogenation activity and oxygenate selectivity and the presence of highly dispersed rhodium on the molybdenum promoted rhodium catalysts are related to the site isolation effect of molybdenum. The parity of rhodium and molybdenum in the catalysts seems to be important for improving oxygenate yield.

The Penn State effort explored the development of new high-surface-area materials for hydrogen storage, materials that could offer enhancement in the hydrogen binding energy through a direct chemical modification of the framework in high specific-surface-area platforms. The team chemically substituted boron into the hexagonal sp2 carbon framework, dispersed metal atoms bound to the boro-carbon structure, and generated the theory of novel nanoscale geometries that can enhance storage through chemical frustration, sheet curvature, electron deficiency, large local fields and mixed hybridization states. New boro-carbon materials were synthesized by high temperature plasma, pyrolysis of boron-carbon precursor molecules, and post-synthesis modification of carbons. Hydrogen uptake has been assessed, and several promising leads have been identified, with the requirement to simultaneously optimize total surface area while maintaining the enhanced hydrogen binding energies already demonstrated.

The advent of carbon-based micro- and nanoelectromechanical systems has revived the interest in glassy carbon, whose properties are relatively unknown at lower dimensions. In this paper, electrical conductivity of individual glassy carbon nanowires was measured as a function of microstructure (controlled by heat treatment temperature) and ambient temperature. The semiconducting nanowires with average diameter of 150 nm were synthesized from polyfurfuryl alcohol precursors and characterized using transmission electron and Raman microscopy. DC electrical measurements made at 90 K to 450 K show very strong dependence of temperature, following mixed modes of activation energy and hopping-based conduction.

Activated carbon materials are complex, noncrystalline solids that are difficult to characterize. In this work microstructure within the sample activated carbons has been elucidated by combining the results from 129 Xe, 1 H NMR spectroscopy and nitrogen porosimetry. Using the Horvath-Kawazoe model to transform nitrogen physiosorpdon data the micropore sizes of the carbons were found to be ~ 5.9A. Evaluation of 129 Xe and 1 H NMR spectra of xenon and adsorbed methane, respectively, provided the chemical shift data necessary to calculate the lateral dimensions of the graphitic microdomains and, hence, those of the pores. By this method, the microdomain sizes were found to vary between 15 and 30A. These values are in good agreement with the sizes of the microdomains expected based on earlier results provided in the literature that show a range from 15 to 60A.

A simplified, first order model of diffusion and reaction in a carbon molecular sieve catalyst for the conversion of synthesis gas to hydrocarbons has been developed. The model identifies the key parameters in determining the expected product distributions from these new catalyst structures. Model results indicate that the carbon molecular sieve catalysts may be tailored to improve the yield of petroleum range products, and provide a useful basis for planning the design, synthesis and testing of these new materials.

Recently, several investigations have focused on promoted rhodium catalysts with particular emphasis on the effects of molybdenum and the utilization of organometallic precursors. Miessner and co-workers have published investigations of bimetallic cluster-derived Rh-Mo catalysts. These cluster-derived catalysts have shown significant oxygenate selectivity in CO hydrogenation when compared with bimetallic catalysts made from metal salts. In their recent paper, Miessner and co-workers excluded molybdenum suboxide migration; instead, they explained that the Mo promotion result in oxidation disruption of Rh[sub x] particles and prevents the sintering of Rh. Similar structural arguments were put forth in earlier work on Rh-Mo catalysts derived from separate rhodium and molybdenum carbonyl precursors. The authors concluded that the role of molybdenum on alumina was to site-isolate rhodium in a highly dispersed form with a higher propensity for oxygenate production than larger rhodium particles. The site-isolated form of rhodium approaches the limit of ultrahigh atomic dispersion through textural promotion. In this investigation of Rh-Mo bimetallic catalysts, the authors provide reactivity and infrared spectral results that indicate the promotion of rhodium by molybdenum leads to a site-isolation effect which is enhanced by synthesis of the catalysts with a bimetallic complex precursor. 9 refs., 2 figs., 3 tabs.

This report details the findings of three years of research plus one year of a no-cost extension. Primary results are the work with supported nanoporous carbon membranes for separation and reaction as well as with cesium-nanoporous carbon catalysts. The work resulted in 17 plus 2 papers (2 are in progress) and partial or full support for five Ph.D. students. Two patents were filed based on this research.

Ultrasonic deposition creates a thin film of polymer on a tubular, macroporous, stainless steel support. Using polyfurfuryl alcohol as the nanoporous carbon precursor and a pyrolysis temperature of 723 kelvin, a membrane was prepared with the following permeances, measured in moles per square meter per Pascal per second: nitrogen, 1.8 × 10 −12 ; oxygen, 5.6 × 10 −11 ; helium, 3.3 × 10 −10 ; and hydrogen, 6.1 × 10 −10 . The ideal separation factors as compared to that for nitrogen are 30:1, 178:1, and 331:1 for oxygen, helium, and hydrogen, respectively.

Glassy carbon is a disordered, nanoporous form of carbon with superior thermal and chemical stability in extreme environments. Freestanding glassy carbon specimens with 4–6 nm thickness and 0.5 nm average pore size were synthesized and fabricated from polyfurfuryl alcohol precursors. Elastic properties of the specimens were measured in situ inside a scanning electron microscope using a custom-built micro-electro-mechanical system. The Young’s modulus, fracture stress and strain values were measured to be about 62 GPa, 870 MPa and 1.3%, respectively; showing strong size effects compared to a modulus value of 30 GPa at the bulk scale. This size effect is explained on the basis of the increased significance of surface elastic properties at the nanometer length-scale.