Roland Marschall

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The conventional polymer electrolyte membrane (PEM) materials for fuel cell applications strongly rely on temperature and pressure conditions for optimal performance. In order to expand the range of operating conditions of these conventional PEM materials, mesoporous functionalised SiO(2) additives are developed. It has been demonstrated that these(More)
Nanometer-sized mesoporous silica particles of around 100-nm diameter functionalized with a large amount of sulfonic acid groups are prepared using a simple and fast in situ co-condensation procedure. A highly ordered hexagonal pore structure is established by applying a pre-hydrolysis step in a high-dilution synthesis approach, followed by adding the(More)
The distribution of SO(3)H-functional groups attached to the ordered inner pore walls of mesoporous Si-MCM-41 materials based on SiO(2) was investigated by gas adsorption combined with in situ small angle neutron scattering (SANS). The functionalization was performed by two different methods, (i) grafting and (ii) co-condensation. The adsorbates N(2) at 77(More)
(111)-layered Ba5Ta4O15 photocatalysts were synthesised by a solid state reaction route and a citrate synthesis route, and their structural and electronic properties were investigated. After citrate route preparation, the presence of a second phase, namely Ba3Ta5O15, was determined by X-ray powder diffraction and absorption spectroscopy. The existence of(More)
Combining different light-absorbing materials for the formation of semiconductor heterojunctions is a very effective strategy for preparing highly active photocatalyst and photoelectrochemical systems. Moreover, the combination of solid state semiconductors with polymers or molecular absorbers expands the possible combinations of materials to alter light(More)
Charge carrier dynamics in phase pure Ba5Ta4O15 and in a Ba5Ta4O15-Ba3Ta5O15 composite have been studied by means of diffuse reflectance laser flash photolysis spectroscopy in the presence and absence of an electron donor, in order to reveal the reason for the improved photocatalytic performance of the latter. For the first time the transient absorption of(More)
In a paired study 12 platelet concentrates (PC) of Fresenius AS-104 cell separator were stored in new polyolefin bags of Fresenius (LE2) and Fenwal PL-732 bags. On day 0 and after 3 and 5 days of storage pH, pO2, pCO2, cell counts, platelet morphology and aggregability, plasma glucose, lactate, LDH and beta TG were determined. The overall changes fell(More)