Particle Synthesis and Non-Equilibrium Solids

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Particle Synthesis and Non-Equilibrium Solids

Univ. Prof. Dr. rer. nat. Oliver Diwald

Lehrstuhl für Feststoff-und Grenzflächenverfahrenstechnik
Friedrich-Alexander-Universität Erlangen-Nürnberg
Cauerstraße 4
D-91058 Erlangen

Tel.: +49 (9131) 85-29404
Fax: +49 (9131) 85-29402
o.diwald@lfg.uni-erlangen.de



Research description

Figure 1: Transmission electron micrographs of MgO nanocubes (1a and b) and titanate nanotubes (1c and d).
(In cooperation with Dr. J. Bernardi, USTEM)

The characterization and quantification of a particular function, such as the optical or chemical activity of an ensemble of small particles, is vital to the development of functional particle systems. Adjustment of their respective behavior requires detailed knowledge about the material specific factors that can be controlled in the course of synthesis and particle processing. Special focus of our work is put on physical and chemical effects that originate from defects in the volume or the interfaces of particles. The only way to effectively enhance the functional properties of a given nanoparticle ensemble – in whatever chemical environment – is a close feedback loop between two activities:
synthesis and processing of nanomaterials, and the physico-chemical characterization of the resulting properties.

Diverse preparative techniques such as chemical vapour synthesis or hydrothermal processing are applied in our lab in order to create samples of nanoparticles with relatively uniform properties (Figure 1).

In addition we are interested

  • to elucidate the mechanism of self-organization during the formation process of shaped metal oxide nanoparticles
  • to tailor the opto-electronic and chemical surface properties of metal-oxide nanoparticles via the choice of synthesis parameters and additional surface functionalization steps
  • to assemble nanoparticles in a controlled way into larger mesoscopically structured networks

Research Projects


Group members

Cooperation Partners

Oliver Diwald's 
	group

Selected publications

  • Sternig, A.; Muller, M.; McCallum, M.; Bernardi, J.; Diwald, O.,
    BaO Clusters on MgO Nanocubes: A Quantitative Analysis of Optical-Powder Properties.
    Small 2010, 6 (4), 582-588.
  • Stankic, S.; Sternig, A.; Finocchi, F.; Bernardi, J.; Diwald, O.,
    Zinc oxide scaffolds on MgO nanocubes.
    Nanotechnology 2010, 21, 355603
  • D'Arienzo, M.; Siedl, N.; Sternig, A.; Scotti, R.; Morazzoni, F.; Bernardi, J.; Diwald, O.,
    Solar Light and Dopant-Induced Recombination Effects: Photoactive Nitrogen in TiO2 as a Case Study.
    Journal of Physical Chemistry C 2010, 114 (42), 18067-18072.
  • Siedl, N.; Elser, M. J.; Halwax, E.; Bernardi, J.; Diwald, O.,
    When Fewer Photons Do More: A Comparative O-2 Photoadsorption Study on Vapor-Deposited TiO2 and ZrO2 Nanocrystal Ensembles.
    Journal of Physical Chemistry C 2009, 113 (21), 9175-9181.
  • Siedl, N.; Elser, M. J.; Bernardi, J.; Diwald, O.,
    Functional Interfaces in Pure and Blended Oxide Nanoparticle Networks: Recombination versus Separation of Photogenerated Charges.
    Journal of Physical Chemistry C 2009, 113 (36), 15792-15795.
  • Riss, A.; Elser, M. J.; Bernardi, J.; Diwald, O.,
    Stability and Photoelectronic Properties of Layered Titanate Nanostructures.
    J Am Chem Soc 2009, 131 (17), 6198-6206.
  • Sternig, A.; Stankic, S.; Muller, M.; Bernardi, J.; Knozinger, E.; Diwald, O.,
    Photoluminescent Nanoparticle Surfaces: The Potential of Alkaline Earth Oxides for Optical Applications.
    Advanced Materials 2008, 20 (24), 4840-4844.
  • Riss, A.; Berger, T.; Stankic, S.; Bernardi, J.; Knozinger, E.; Diwald, O.,
    Charge separation in layered titanate nanostructures: Effect of ion exchange induced morphology transformation.
    Angewandte Chemie-International Edition 2008, 47 (8), 1496-1499.
  • Muller, M.; Sternig, A.; Stankic, S.; Stoger-Pollach, M.; Bernardi, J.; Knozinger, E.; Diwald, O.,
    Nanoparticles as a support: CaO deposits on MgO cubes.
    Journal of Physical Chemistry C 2008, 112 (25), 9120-9123.
  • Sterrer, M.; Berger, T.; Diwald, O.; Knozinger, E.; Allouche, A.,
    Ozonide ions on the surface of MgO nanocrystals.
    Top Catal 2007, 46 (1-2), 111-119.
  • Stankic, S.; Bernardi, J.; Diwald, O.; Knozinger, E.,
    Photoexcitation of local surface structures on strontium oxide grains.
    Journal of Physical Chemistry C 2007, 111 (22), 8069-8074.
  • Riss, A.; Berger, T.; Grothe, H.; Bernardi, J.; Diwald, O.; Knozinger, E.,
    Chemical control of photoexcited states in titanate nanostructures.
    Nano Letters 2007, 7 (2), 433-438.
  • Muller, M.; Stankic, S.; Diwald, O.; Knozinger, E.; Sushko, P. V.; Trevisanutto, P. E.; Shluger, A. L.,
    Effect of protons on the optical properties of oxide nanostructures.
    J Am Chem Soc 2007, 129 (41), 12491-12496.
  • Berger, T.; Schuh, J.; Sterrer, M.; Diwald, O.; Knozinger, E.,
    Lithium ion induced surface reactivity changes on MgO nanoparticles.
    Journal of Catalysis 2007, 247 (1), 61-67.
  • Berger, T.; Diwald, O.; Knozinger, E.; Napoli, F.; Chiesa, M.; Giamello, E.,
    Hydrogen activation at TiO2 anatase nanocrystals.
    Chem Phys 2007, 339 (1-3), 138-145.
  • Stankic, S.; Bernardi, J.; Diwald, O.; Knozinger, E.,
    Optical surface properties and morphology of MgO and CaO nanocrystals.
    J Phys Chem B 2006, 110 (28), 13866-13871.
  • Elser, M. J.; Berger, T.; Brandhuber, D.; Bernardi, J.; Diwald, O.; Knozinger, E.,
    Particles coming together: Electron centers in adjoined TiO2 nanocrystals.
    J Phys Chem B 2006, 110 (15), 7605-7608.
  • Berger, T.; Diwald, O.; Knozinger, E.; Sterrer, M.; Yates, J. T.,
    UV induced local heating effects in TiO2 nanocrystals.
    Phys Chem Chem Phys 2006, 8 (15), 1822-1826.