Institut für Anorganische Chemie und Kristallographie
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Item-typ:Veröffentlichung, Microbial fuel cell performance of graphitic carbon functionalized porous polysiloxane based ceramic membranes(Elsevier, 2019-06-25); ; ; ; Proton-conducting porous ceramic membranes were synthesized via a polymer-derived ceramic route and probed in a microbial fuel cell (MFC). Their chemical compositions were altered by adding carbon allotropes including graphene oxide (GO) and multiwall carbon nanotubes into a polysiloxane matrix as filler materials. Physical characteristics of the synthesized membranes such as porosity, hydrophilicity, mechanical stability, ion exchange capacity, and oxygen mass transfer coefficient were determined to investigate the best membrane material for further testing in MFCs. The ion exchange capacity of the membrane increased drastically after adding 0.5 wt% of GO at an increment of 9 fold with respect to that of the non-modified ceramic membrane, while the oxygen mass transfer coefficient of the membrane decreased by 52.6%. The MFC operated with this membrane exhibited a maximum power density of 7.23 W m-3 with a coulombic efficiency of 28.8%, which was significantly higher than the value obtained using polymeric Nafion membrane. Hence, out of all membranes tested in this study the GO-modified polysiloxane based ceramic membranes are found to have a potential to replace Nafion membranes in pilot scale MFCs.Wissenschaftlicher ArtikelBand:129125 161 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Reactivity and redox behaviour of ferrocenyl substituted pnictogens and chalcogens(2025-06-13); ; 24 42 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Highly Active Sm2O3‐Ni Xerogel Catalysts for CO2 Methanation(Chemistry Europe, 2019-01-10); ; ; ; We report on a new synthesis route for pure Sm2O3 and Sm2O3-Ni xerogels by modifying the well-known epoxide addition method. The resulting xerogels are used to prove the suitability of samaria as a highly effective catalyst support and to determine the optimal Ni loading. Therefore, a set of five catalysts with Ni loadings between 4 wt % and 89 wt % Ni was prepared and fully characterized by X-ray diffraction, N2 physisorption, transmission electron microscopy and H2 temperature-programmed reduction. Catalytic measurements reveal that the catalyst with 39 wt % Ni shows the best catalytic performance, outperforming even highly active literature known systems. Stability runs indicate that the catalyst deactivates independently of the Ni loading as well as conversion level over 600 min due to, most likely, carbonate formation. This deactivation, however, is reversible by a simple regeneration step. As shown by simultaneous CO2/CO methanation measurements, the Ni−Sm2O3 catalysts are also highly efficient for CO methanation. In this case, CO is preferentially converted to methane compared to CO2.Wissenschaftlicher ArtikelBand:11Heft:6106 151 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Photocatalytic activity of TiO2 layers produced with plasma electrolytic oxidation(2018-06-25); ; ; The photocatalytic activity of titanium dioxide (TiO2) results from its crystalline phase's anatase and rutile. In this regard, plasma electrolytic oxidation (PEO) is a promising process for producing highly porous surfaces with a high proportion of crystalline phases into the oxide layer on pure titanium. PEO-coatings were produced under different conditions in various electrolytes in order to identify the crystalline fractions of the surfaces and to examine the associated photocatalytic activity. The composition of the PEO electrolyte was varied to optimize the polymorphic composition of the TiO2 comparable to the photocatalytic active TiO2 material AEROXIDE® P25. X-ray powder diffraction (XRD) was selected to identify the produced crystal structures of anatase and rutile on the surface material depending on the electrolytic system. In order to establish the expected band gap of the TiO2 on the surfaces, the samples were subjected to a diffuse reflectance measurement, which detected direct transitions for all samples using the TAUC and DASF methods. The acceptance of the photocatalytic reaction by the crystalline PEO-samples was further confirmed by the degradation of two typical dyes (methylene blue MB, rhodamine B RB) under UV-light irradiation. Both a high proportion of anatase and the presence of rutile on the PEO-layers had a targeted effect on the catalytic efficiency. However, the average crystallite sizes also played an important role in the samples produced in an optimum range of 30–40 nm. Both effects support the photocatalytic properties of PEO-surfaces.Wissenschaftlicher Artikel394 430