Holger Ruland

Metal–support interactions in surface-modified Cu–Co catalysts applied in higher alcohol synthesis

Cu–Co-based model catalysts were prepared by a sophisticated alkali-free synthesis method and tested in the conversion of synthesis gas to higher alcohols. MoO3-coated alumina was used as the support, providing both high specific surface area and strongly interacting sites for the deposition of the active metals. A bulk Cu/Co ratio of ~2 was found to be most suitable in terms of activity and product distribution. Surface enrichment of Mo for all samples was observed by XPS, which significantly influenced the performance of the catalysts. Mo was found to be both a structural and a chemical promoter. Strong metal–support interactions were further achieved by modification of alumina with magnesia. With 12 wt% Mg incorporated, the catalysts showed 40% total oxygenate selectivity including 11% selectivity to ethanol.

CO 2 hydrogenation to hydrocarbons over iron nanoparticles supported on oxygen-functionalized carbon nanotubes

AbstractHydrogenation of CO2 to hydrocarbons over iron nanoparticles supported on oxygen-functionalized multi-walled carbon nanotubes was studied in a fixed-bed U-tube reactor at 25 bar with a H2:CO2 ratio of 3. Conversion of CO2 was approximately 35% yielding C1–C5 products at 360 ∘C with methane and CO as major products. The CO2 equilibrium conversion for temperatures in the range of 320 ∘ to 420∘C was analysed by using CHEMCAD simulation software. Comparison between experimental and simulated degrees of CO2 conversion shows that reverse water gas shift equilibrium had been achieved in the investigated temperature range and that less than 47% of CO2 can be converted to CO at 420∘C. ᅟ.CO2 hydrogenation to short chain hydrocarbons was achieved using iron nanoparticles supported on oxygen-functionalized carbon nanotubes. The conversion of CO2 was found to be limited by the reverse water gas shift equilibrium in the temperature range from 320° to 420°C.

Palladium Nanoparticles Supported on Nitrogen-Doped Carbon Nanotubes as a Release-and-Catch Catalytic System in Aerobic Liquid-Phase Ethanol Oxidation

Pd nanoparticles supported on carbon nanotubes were applied in the selective oxidation of ethanol in the liquid phase. The characterization of the surface and bulk properties combined with the catalytic tests indicated the dissolution and redeposition of Pd under the reaction conditions. A dynamic interplay within the Pd life cycle was identified to be responsible for the overall reactivity. Nitrogen‐doped carbon nanotubes were found to act as an excellent support for the Pd catalyst system by efficiently stabilizing and recapturing the Pd species, which resulted in high activity and selectivity to acetic acid.