Dan Meisel Hebrew University of Jerusalem, Israel: B. Sc. (1967), M. Sc. (1969), and Ph. D. (1974) Phone (574) 631-5457 Fax (574) 631-3646 e-mail: dani@nd.edu Photochemically and radiolytically induced processes at the nanoscale

Scientific Interests

Energy and Charge Transfer across Interfaces -Excitation and ionization in nanoparticles in suspension lead to unusual processes, in particular at the nanoscale and across interfaces.

(A) Changes in a particle in response to external chemical reactions. Left-hand side – electron transfer reduces Ag+ but is accompanied by proton transfer; Right-hand side - addition of Ag+.
(B) Changes in Fermi-level energy in response to the chemical processes shown in (A). The dashed red double-arrow indicates the energy-dependent vibronic coupling of the Fermi level to the ground state.

Catalytic Processes on Nanoparticles – Nanoparticles are efficient redox catalysts. The underlying mechanisms are fundamentally interesting and of practical importance.

Solar Energy Conversion and Environmental Implications - The basic principles of the phenomena mentioned above are of direct implications to power generation in nuclear plants, to the conversion of solar energy into chemicals, to environmental effects of energy generation & utilization, and to the use of ionizing radiation in radiotherapy.

Radical-Particle Interactions in Metallic Nanoparticles – Reducing radicals react with metallic particles by electron-transfer, followed by proton-transfer reactions, ultimately leading to molecular hydrogen evolution. Using recently developed synthetic methods to obtain well-characterized particles with clean surfaces in suspensions and applying radiolytic and photolytic methods in combination with the ultra-sensitive surface enhanced Raman spectroscopy we study the mechanism of hydrogen evolution from water and other reductive processes on metallic particles. Electronic changes in molecular probes at the particles surface, their orientation relative to the surface, the effect of charge density in the particle and the effect of pH were outlined.

Charge Separation in Nanotube Structures– We designed and constructed with our colleagues at the Weizmann Institute of Science in Israel nanotube structures that might be useful in solar energy conversion. The backbone of the nanotubes are metallic nanoparticles attached to TiO2 in the exterior of the tube. Modified dye sensitizer were attached to the exterior well and photo-induced charge transfer to the tube has been demonstrated. It is suggested that these constructs could serve as efficient light collectors and at the same time provide a mechanism for separation of the oxidizing and reducing half-cycles in energy conversion devices.

G. Merga, L.C. Cass, D.M. Chipman and D. Meisel
Probing silver nanoparticles during catalytic H₂ evolution
J. Am. Chem. Soc. 2008 130, 7067-76 link

G. Merga, R. Wilson, G. Lynn, B. H. Milosavljevic, and D. Meisel
Redox catalysis on “naked” silver nanoparticles
J. Phys. Chem. C 2007 111, 12220-6 link

T. Zidki, H. Cohen, D. Meyerstein and D. Meisel
Effect of silica-supported silver nanoparticles on dihydrogen yields from irradiated aqueous solutions
J. Phys. Chem. C 2007 111, 10461-6 link

G. Merga, B.H. Milosavljevic and D. Meisel
Radiolytic yields in aqueous suspensions of gold particles
J. Phys. Chem. B, 2006 110, 5403-8 link

Supported by the Division of
Chemical Sciences
Office of
Basic Energy Sciences
at the
U.S. Department of Energy

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Last Modified: 04/22/2009