Rüdiger Kötz

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Nanoparticles are key components in the advancement of future energy technologies, thus, strategies for preparing nanoparticles in large volume by techniques that are cost-effective are required. In the substitution of fossil-fuels by renewable energy resources, nanometer-sized particles play a key role for synthesizing energy vectors from varying and(More)
The electronic properties of citrate stabilised Ag nanoparticles with sizes ranging from 4 to 35 nm were investigated by the Kelvin probe method and high resolution XPS. Two and three dimensional assemblies of the particles were prepared by electrostatic adsorption from aqueous solution onto poly-l-lysine modified surfaces. The work function of the Ag(More)
Suspension cultures of Coffea arabica L. are a useful source for methyltransferase preparations of high activity catalysing the transfer of methylgroups from S-adenosyl-L-methionine to 7-methylxanthine and to theobromine producing theobromine and caffeine respectively. Surprisingly, these enzyme activities are not correlated with the availability of(More)
In recent years, the oxygen evolution reaction (OER) has attracted increased research interest due to its crucial role in electrochemical energy conversion devices for renewable energy applications. The vast majority of OER catalyst materials investigated are metal oxides of various compositions. The experimental results obtained on such materials strongly(More)
The development of stable catalyst systems for application at the cathode side of polymer electrolyte fuel cells (PEFCs) requires the substitution of the state-of-the-art carbon supports with materials showing high corrosion resistance in a strongly oxidizing environment. Metal oxides in their highest oxidation state can represent viable support materials(More)
In this work, high surface area antimony doped tin oxide (Sb-SnO2) has been synthesized using a modified sol-gel synthesis method. The bulk and surface properties of the metal oxide support have been investigated as a function of the processing conditions. A change in the Sb-SnO2 processing conditions, while preserving an overall invariant bulk composition,(More)
The effect of water contamination in 1 mol L -1 Et4NBF4 dissolved in acetonitrile or in propylene carbonate as electrolyte on the capacitance fading of activated carbon based electrochemical double layer capacitors has been investigated during constant voltage load tests at 2.75 V and 3.5 V cell voltage. For a cell voltage of 2.75 V, water contamination in(More)
Fabrication of PPy Nanoparticles: For the synthesis of the PPy nanoparticles with an average diameter of 2 nm, octyltrimethylammo-nium bromide (OTAB; 6.0 g) was magnetically stirred in 40 mL of distilled water at 3 C. Pyrrole (1.0 g) was then added dropwise to the surfactant solution, and iron(III) chloride (5.561 g) dissolved in a small amount of distilled(More)
Poly(dimethylsiloxane) (PDMS) was irradiated under ambient conditions in air with a Xe2-excimer lamp. The formation of atomic oxygen and ozone during irradiation in air by V-UV photons results in the transformation of PDMS to silicon oxide. The irradiated surfaces were studied by spectroscopic ellipsometry and neutron reflectometry. The measurements(More)