Marga‐Martina Pohl

Hydrodeoxygenation of Phenol as a Model Compound for Bio‐oil on Non‐noble Bimetallic Nickel‐based Catalysts

Ni/HZSM‐5 catalysts for the hydrodeoxygenation of bio‐oil were modified with Cu and Co. A first test series with phenol as a model revealed that the presence of Ni is essential for high activity. However, modification with Cu deteriorated the catalytic performance significantly whereas an admixture of Co increased the activity and selectivity toward the target hydrocarbons benzene and cyclohexane. Characterization studies performed by using TEM, X‐ray photoelectron spectroscopy, and XRD techniques elucidated detrimental effects of the second metals: both Cu and Co form alloys with Ni; however, Cu caused a loss of active sites as well as tended to segregate at the surface whereas Co made the particles smaller and strongly stabilized the active Ni sites, that is, Ni dispersion increased. A NiCo/HZSM‐5 catalyst (10 wt % of each metal content) showed 99 % hydrocarbon selectivity at complete phenol conversion. Additional studies using intermediate products such as benzene, cyclohexene, and C6 oxygenates as feeds highlight the effect of the catalyst composition on key reaction steps.

Superior activity of rutile-supported ruthenium nanoparticles for HCl oxidation

The activity of supported Ru-based catalysts in the oxidation of HCl to Cl2 is shown to be strongly affected by active phase–support interactions and by the way of incorporation of the Ru species. Depositing colloidally prepared Ru nanoparticles on a rutile carrier results in catalysts attaining very high and stable HCl conversion levels under industrially-relevant conditions using ruthenium loadings as low as 0.16 wt%.

Design of BODIPY Dyes as Photosensitisers in Multicomponent Catalyst Systems for Light-Driven Hydrogen Production

A study of visible-light-driven hydrogen production using a multicomponent system consisting of different boron dipyrromethene (BODIPY) dyes, triethylamine and [{Pd(PPh3)Cl2}2] from THF/water mixtures is presented. A trio of meso-mesityl BODIPY dyes display the best activities and long-term stabilities of more than ten days with the 2,6-diiodo derivative showing the best performance.

New Insights into the Nature of Co-components and Their Impact on Pd Structure: X-ray Absorption Studies on Toluene Acetoxylation Catalysts.

Co-components are a powerful tool to tune the performance of catalysts, but their nature and their impact on the catalysts is often controversially discussed. In this study X-ray absorption spectroscopy (XAS) was employed to elucidate the nature of co-components and their impact on the catalytic reaction. In anatase-supported Pd-based catalysts for the gas-phase acetoxylation of toluene, less noble co-components (e.g., Mn, Co, and Sb) spread over the support in their oxidic form and changed their valence state on stream. Incorporated atoms such as C or a small part of the Sb affect the electronic structure of Pd. For the noble Au, only a weak interaction with the support and Pd was observed during time on stream. Only XAS at the K-edges together with investigations of the Pd L-edge for a better understanding of the electronic structure, supplemented by STEM for elemental mapping, allow such detailed insights.