The depolymerization of lignocellulosic feedstock with a heterogeneous composition is a major challenge and usually leads to the formation of monosaccharides as main products. Our work aims to convert such...

The copper-catalyzed electrochemical CO 2 reduction reaction represents an elegant pathway to reduce CO 2 emissions while producing a wide range of valuable hydrocarbons. The selectivity for these products depends strongly on the structure and morphology of the copper catalyst. However, continued deactivation during catalysis alters the obtained product spectrum. In this work, we report on the stabilizing effect of three different carbon supports with unique pore structures. The influence of pore structure on stability and selectivity was examined by high-angle annular dark field scanning transmission electron microscopy and gas chromatography measure-ments in a micro-flow cell. Supporting particles into confined space was found to increase the barrier for particle agglomeration during 20 h of chronopotentiometry measurements at 100 mA cm À 2 resembling long-term CO 2 reduction conditions. We propose a catalyst design preventing coalescence and agglomeration in harsh electrochemical reaction conditions, exemplarily demonstrated for the electrocatalytic CO 2 reduction. With this work, we provide important insights into the design of stable CO 2 electrocatalysts that can potentially be applied to a wide range of applications.[a] E.

Efficient base-modulated product selectivity in the aqueous-phase Ru/C-catalyzed reductive amination of 1,6hexanediol (HDO) was reported by performing the reaction at mild conditions (463 K, 25 bar H 2 ). High selectivity of amines could be controlled by the addition of different bases; for example, Cs 2 CO 3 addition gave a high yield of 6-amino-1-hexanol (AH, 26%). However, the addition of Ba(OH) 2 resulted in the formation of high yield of secondary amination products, hexamethylenediamine (HMDA, 34%) and azepane (26%). The hydroxide base, especially Ba(OH) 2 , aids in the initial conversion of HDO to AH by significantly decreasing the apparent activation energy from 68 to 48 kJ mol −1 . A closer analysis of the formation of secondary products (azepane and HMDA) revealed a faster reaction between NH 3 and the carbonyl-containing intermediate by the addition of Ba(OH) 2 into the reaction solution.

The depolymerization of lignocellulosic feedstock with a heterogeneous composition is a major challenge and usually leads to the formation of monosaccharides as main products. Our work aims to convert such feedstock into oligomeric glycans as more valuable products compared to sugars, by using mechanocatalysis in a planetary ball mill in a cost-efficient and resource-saving manner. Herein, we utilized raw materials such as wheat straw, beet pulp, cocoa shells and apple pomace as residual natural raw materials from food and feed production. Reaction parameters such as rotational speed, acid content and milling duration were investigated and optimized towards a maximum amount of soluble species and a minimum of monosaccharides. The optimization for cellulose as substrate resulted in a nearly full-soluble fraction containing oligomeric glycans. Based on these results the reaction parameters were transferred and further optimized for lignocellulosic feedstock. For wheat straw a solubility of over 90 % was achieved comprising a mixture of oligomeric glycans as well as partially depolymerized lignin.