Co-based layered double hydroxide (LDH) catalysts with Fe and Al contents in the range of 15 to 45 at % were synthesized by an efficient coprecipitation method. In these catalysts, Fe or Al ions play an essential role as trivalent species to stabilize the LDH structure. The obtained catalysts were characterized by a comprehensive combination of surface- and bulk-sensitive techniques and were evaluated for the oxygen evolution reaction (OER) on rotating disk electrodes. The OER activity decreased upon increasing the Al content for the Co- and Al-based LDH catalysts, whereas a synergistic effect in Co- and Fe-based LDHs was observed, which resulted in an optimal Fe content of 35 at %. This catalyst was spray-coated on Ni foam electrodes and showed very good stability in a flow-through cell with a potential of approximately 1.53 V at 10 mA cm in 1 m KOH for at least 48 h.

The combination of a nonthermal plasma and a heterogeneous catalyst provides unique opportunities for chemical transformations. High densities of reactive species, such as ions, radicals or vibrationally excited molecules, are generated by electron collisions and initiate a multitude of chemical reactions in the gas phase. By shifting the reaction site from the gas phase to the surface of the catalyst, the selectivity of these reactions can be significantly enhanced. Dielectric barrier discharges (DBDs) are a promising plasma source for these kinds of applications due to their non‐equilibrium conditions and their simple construction. This review provides a brief introduction to the breakdown mechanism and the various geometries of DBDs and presents several plasma‐catalytic DBD applications.

(2017). Encapsulation of bimetallic metal nanoparticles into robust Zr-based metal-organic frameworks: Evaluation of the catalytic potential for sizeselective hydrogenation. Abstract: The realization of metal NPs with bimetallic character and distinct composition for specific catalytic applications is an intensively studied field. Due to the synergy between metals, most of the bimetallic particles exhibit unique properties, only hardly provided by the individual monometallic counterparts. However, as small sized NPs possess high surface energy, agglomeration during catalytic reactions is favored. Sufficient stabilization can be achieved by confinement of NPs in porous support materials. In this sense, especially MOFs gained a lot of attention during the last years, however, encapsulation of bimetallic species remains challenging. Herein, the exclusive embedding of preformed core/shell PdPt and RuPt NPs into chemically robust Zr-based MOFs is presented. Microstructural characterization manifests partial retention of the core/shell systems after successful encapsulation without harming the crystallinity of the microporous support. The resulting chemically robust NP@UiO-66 materials exhibit enhanced catalytic activity towards the liquid-phase hydrogenation of nitrobenzene, competitive with commercially used Pt on activated carbon, but with simultaneous superior size-selectivity for sterically varying substrates.

A twin surface dielectric barrier discharge is used for the catalyst‐enhanced plasma oxidation of 300 ppm n‐butane in synthetic air. Plasma‐only operation results in the conversion of n‐butane into CO and CO2. Conversion is improved by increasing the temperature of the feed gas, but selectivity shifts to undesired CO. α‐MnO2 is used as a catalyst deposited on the electrodes by spray coating with a distance of 1.5 mm between the uncoated grid lines and the square catalyst patches to prevent the inhibition of plasma ignition. The catalyst strongly influences selectivity, reaching 40% conversion and 73% selectivity to CO2 at a specific energy density of 390 J·L−1 and 140°C, which is far below the onset temperature of thermocatalytic n‐butane conversion.

A series of novel Pd@DE-HKUST-1(Cu/Pd) catalysts with different pydc feeding ratios were successfully synthesized. The size regime and the spatial distribution of the Pd NPs can be controlled by the amount of framework incorporated pydc.