Books and Chapters

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Challenges in Water Electrolyzer
Challenges in Water Electrolyzer
Ru-Embedded Carbon Fabric
Ru-Embedded Carbon Fabric
Amine Chemistry of Porous CO2 Adsorbents
Amine Chemistry of Porous CO2 Adsorbents
Boronization of Nickel Foam for Sustainable Electrochemical Reduction of Nitrate to Ammonia
Boronization of Nickel Foam for Sustainable Electrochemical Reduction of Nitrate to Ammonia
How Reproducible are Surface Areas Calculated from the BET Equation?
How Reproducible are Surface Areas Calculated from the BET Equation?
Extensive Screening of Solvent-linked Porous Polymers through Friedel-Crafts Reaction for Gas Adsorption
Extensive Screening of Solvent-linked Porous Polymers through Friedel-Crafts Reaction for Gas Adsorption
Alkyl-linked porphyrin porous polymers for gas capture and precious metal adsorption
Alkyl-linked porphyrin porous polymers for gas capture and precious metal adsorption
Quantifying the nitrogen effect on CO2 capture using isoporous network polymers
Quantifying the nitrogen effect on CO2 capture using isoporous network polymers
Direct Access to Primary Amines and Particle Morphology Control in Nanoporous CO2 Sorbents
Direct Access to Primary Amines and Particle Morphology Control in Nanoporous CO2 Sorbents
Enhanced Sorption Cycle Stability and Kinetics of CO2 on Lithium Silicates Using the Lithium Ion Channeling Effect of TiO2 Nanotubes
Enhanced Sorption Cycle Stability and Kinetics of CO2 on Lithium Silicates Using the Lithium Ion Channeling Effect of TiO2 Nanotubes
  • Pd-sensitized single vanadium oxide nanowires: highly-responsive hydrogen sensing based on the Mott transition

    J. M. Baik, M. H. Kim, C. Larson, C. T. Yavuz, G. D. Stucky, A. M. Wodtke, M. Moskovits
    Nano Lett., 9 (12), 3980–3984
    2009
    Pd-sensitized single vanadium oxide nanowires: highly-responsive hydrogen sensing based on the Mott transition
    Exceptionally sensitive hydrogen sensors were produced using Pd-nanoparticle-decorated, single vanadium dioxide nanowires. The high-sensitivity arises from the large downward shift in the insulator to metal transition temperature following the adsorption on and incorporation of atomic hydrogen, produced by dissociative chemisorption on Pd, in the VO2, producing ∼1000-fold current increases. During a rapid initial process, the insulator to metal transition temperature is decreased by >10 °C even when exposed to trace amounts of hydrogen gas. Subsequently, hydrogen continues to diffuse into the VO2 for several hours before saturation is achieved with only a modest change in the insulator to metal transition temperature but with a significant increase in the conductivity. The two time scales over which H-related processes occur in VO2 likely signal the involvement of two distinct mechanisms influencing the electronic structure of the material one of which involves electron−phonon coupling pursuant to the modification of the vibrational normal modes of the solid by the introduction of H as an impurity.
  • Growth of metal oxide nanowires from supercooled liquid nanodroplets

    , M. H. Kim, B. Lee, S. Lee, C. Larson, J. M. Baik, C. T. Yavuz, S. Seifert, S. Vajda, R. E. Winans, M. Moskovits, G. D. Stucky, A. M. Wodtke
    Nano Lett., 9 (12), 4138–4146
    2009
    Growth of metal oxide nanowires from supercooled liquid nanodroplets
    Nanometer-sized liquid droplets formed at temperatures below the bulk melting point become supercooled as they grow through Ostwald ripening or coalescence and can be exploited to grow nanowires without any catalyst. We used this simple approach to synthesize a number of highly crystalline metal oxide nanowires in a chemical or physical vapor deposition apparatus. Examples of nanowires made in this way include VO2, V2O5, RuO2, MoO2, MoO3, and Fe3O4, some of which have not been previously reported. Direct evidence of this new mechanism of nanowire growth is found from in situ 2-dimensional GISAXS (grazing incidence small angle X-ray scattering) measurements of VO2 nanowire growth, which provides quantitative information on the shapes and sizes of growing nanowires as well as direct evidence of the presence of supercooled liquid droplets. We observe dramatic changes in nanowire growth by varying the choice of substrate, reflecting the influence of wetting forces on the supercooled nanodroplet shape and mobility as well as substrate−nanowire lattice matching on the definition of nanowire orientation. Surfaces with defects can also be used to pattern the growth of the nanowires. The simplicity of this synthesis concept suggests it may be rather general in its application.
  • Markedly improved CO2 capture efficiency and stability of gallium substituted hydrotalcites at elevated temperatures

    C. T. Yavuz, B. D. Shinall, A. V. Iretskii, M. G. White, T. Golden, M. Atilhan, P. C. Ford, G. D. Stucky
    Chem. Mater., 21 (15), 3473-3475
    2009
  • Applying analytical ultracentrifugation to nanocrystal suspensions

    J. A. Jamison, K. M. Krueger, J. T. Mayo, C. T. Yavuz, J. J. Redden, V. L. Colvin
    Nanotechnology, 20, 355702-12
    2009
    Applying analytical ultracentrifugation to nanocrystal suspensions
    While applied frequently in physical biochemistry to the study of protein complexes, the quantitative use of analytical ultracentrifugation (AUC) for nanocrystal analysis is relatively rare. Its application in nanoscience is potentially very powerful as it provides a measure of nanocrystal density, size and structure directly in the solution phase. Towards that end, this paper examines the best practices for applying data collection and analysis methods for AUC, geared towards the study of biomolecules, to the unique problems of nanoparticle analysis. Using uniform nanocrystals of cadmium selenide, we compared several schemes for analyzing raw sedimentation data. Comparable values of the mean sedimentation coefficients (s-value) were found using several popular analytical approaches; however, the distribution in sample s-values is best captured using the van Holde–Weischt algorithm. Measured s-values could be reproducibly collected if sample temperature and concentration were controlled; under these circumstances, the variability for average sedimentation values was typically 5%. The full shape of the distribution in s-values, however, is not easily subjected to quantitative interpretation. Moreover, the selection of the appropriate sedimentation speed is crucial for AUC of nanocrystals as the density of inorganic nanocrystals is much larger than that of solvents. Quantitative analysis of sedimentation properties will allow for better agreement between experimental and theoretical models of nanocrystal solution behavior, as well as providing deeper insight into the hydrodynamic size and solution properties of nanomaterials.
  • Magnetic separations: From steel plants to biotechnology

    C. T. Yavuz, A. Prakash, J. T. Mayo, V. L. Colvin
    Chem. Eng. Sci., 64, 10, 2510-2521
    2009
    Magnetic separations: From steel plants to biotechnology
    Magnetic separations have for decades been essential processes in diverse industries ranging from steel production to coal desulfurization. In such settings magnetic fields are used in continuous flow processes as filters to remove magnetic impurities. High gradient magnetic separation (HGMS) has found even broader use in wastewater treatment and food processing. Batch scale magnetic separations are also relevant in industry, particularly biotechnology where fixed magnetic separators are used to purify complex mixtures for protein isolation, cell separation, drug delivery, and biocatalysis. In this review, we introduce the basic concepts behind magnetic separations and summarize a few examples of its large scale application. HGMS systems and batch systems for magnetic separations have been developed largely in parallel by different communities. However, in this work we compare and contrast each approach so that investigators can approach both key areas. Finally, we discuss how new advances in magnetic materials, particularly on the nanoscale, as well as magnetic filter design offer new opportunities for industries that have challenging separation problems.
  • Size-dependent sedimentation properties of nanocrystals

    J. A. Jamison, K. M. Krueger, C. T. Yavuz, J. T. Mayo, D. LeCrone, J. J. Redden, V. L. Colvin
    ACS Nano 2, 311-319
    2008
    Size-dependent sedimentation properties of nanocrystals
    Centrifugation is an increasingly important technique for nanomaterial processing. Here, we examine this process for gold, cadmium selenide, and iron oxide nanocrystals using an analytical ultracentrifuge. Such data provide an accurate measure of the sedimentation coefficients for these materials, and we find that this parameter has a significant dependence on the size and surface coating. Conventional models for particle sedimentation cannot capture the behavior of these nanocrystals unless the density of the nanocrystals is described by a size-dependent term that accounts for both the inorganic core and the organic coating. Using this modification in the particle sedimentation framework, it is possible to estimate sedimentation coefficients from information about the nanocrystal core and surface coating dimensions. Such data are useful in choosing the speeds for a centrifugation process and are particularly important when bimodal nanocrystal distributions are present.

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