Topics in Catalysis Journal
The poisoning of Pd-Pt/Al2O3 and Pd-Pt/CeO2-ZrO2-Y2O3-La2O3 methane oxidation catalysts by SO2 was studied under conditions typical for lean burn gas engines. Regeneration of sulfur-poisoned catalysts was achieved by applying rich conditions at 500 and 550 °C.
Angewandte Chemie Journal
A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (<500°C) and exploited to enhance the catalytic activity of Pt/CeO2-based exhaust gas catalysts.
Journal of the American Chemical Society
The use of Metal-Organic Frameworks as crystalline matrices for the synthesis of multiple component or multivariate solids by the combination of different linkers into a single material has emerged as a versatile route to tailor the properties of single-component phases or even access new functions.
European Polymer Journal
Pentafluorophenyl methacrylate (PFPMA) and pentafluorophenyl acrylate (PFPA) are frequently used monomers to produce advanced materials for biomedical applications via (co)polymerization reactions. This contribution reports kinetic investigations of the reversible addition fragmentation chain transfer (RAFT) copolymerization of PFPMA and methyl methacrylate (MMA) mediated by a dithiobenzoate chain transfer agent (CTA) at 70°C in dimethyl formamide (DMF).
Journal of Drug Delivery Science and Technology
The use of poly(vinyl alcohol) (PVA) and a PVA-sodium dodecyl sulfate mixture (PVA-SDS) for the colloidal stabilization of poly(DL-lactide) (PDLLA) and poly(DL-lactide-co-glycolide) (PLGA) nanoparticles (NPs) loaded with paclitaxel (PTX) was investigated.
The Collaborative Research Centre PolyTarget is developing polymer-based, nanoparticulate carrier materials for the targeted application of active pharmaceutical ingredients. In the foreground are systems that are suitable for the treatment of diseases and syndromes whose morbidity is significantly characterized by an inflammatory reaction. The collaborative research centre PolyTarget is funded by the German Research Foundation (DFG). Spokesman ist Prof. Dr. Ulrich S. Schubert.
International Journal of Hydrogen Energy Journal
Mono-metallic Pt and Rh catalysts supported on both CeO2 and TiO2 were prepared and tested for water-gas shift activity in a Flowrence, high-throughput reactor system. The feed composition mimicked a typical fuel processor, steam methane reformer outlet stream. The Pt/CeO2 catalyst showed the best metal activity of ∼3.8 E-07 moles CO converted·gPt-1 s-1, at a Pt loading of 0.5 wt%, activity decreasing with increasing metal loading. Furthermore, the Pt/CeO2 catalyst produced almost no methane while the Rh based catalysts led to substantial methanation.
Applied Catalysis B: Environmental Journal
Pd-Pt/Al2O3 and Pd-Pt/CeO2-ZrO2-Y2O3-La2O3 methane oxidation catalysts were investigated under typical lean-burn gas engine conditions with respect to sulfur poisoning and during reactivation, particularly under the most efficient rich conditions. Sulfation of the noble metal and the support material led to pronounced catalyst deactivation. A pronounced transfer of sulfates to the support, particularly alumina, only partially protects the noble metal. In situ X-ray absorption spectroscopy gave insight into the nature and evolution of Pd species during regenerative treatment. Although palladium sulfate that formed during poisoning is decomposed at approximately 200°C in oxygen-free conditions, support regeneration requires higher temperatures, which result in PdS formation above 400°C. Despite its high stability under rich conditions, PdS decomposition by oxidation in lean atmosphere leads to the recovery of the activity. In addition, water vapor that is present during the rich regeneration exhibited a beneficial effect on the regeneration with higher catalytic activity after regeneration.
Nature Catalysis Journal
Platinum single sites are highly attractive due to their high atom economy and can be generated on CeO2 by an oxidative high-temperature treatment. However, their location and activity are strongly debated. Furthermore, reaction-driven structural dynamics have not been addressed so far. In this study, we were able to evidence platinum-induced CeO2 surface restructuring, locate platinum single sites on CeO2 and track the variation of the active state under reaction conditions using a complementary approach of density functional theory calculations, in situ infrared spectroscopy, operando high-energy-resolution fluorescence detected X-ray absorption spectroscopy and catalytic CO (as well as C3H6 and CH4) oxidation. We found that the onset of CO oxidation is linked to the migration of platinum single sites from four-fold hollow sites to form small clusters containing a few platinum atoms. This demonstrates that operando studies on single sites are essential to assess their fate and the resulting catalytic properties.