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The catalytic performance of a set of technical, zeolite ZSM‐5 extruded materials have been studied in a bench scale unit for the ex‐situ Catalytic Fast Pyrolysis (CFP) of lignocellulosic biomass. The set of catalysts include micro‐ and mesoporous materials, with and without ZrO2‐promotion, with different Si/Al ratios and with micro‐ and nanosized zeolite crystals. Mesoporosity, acidity and crystal size play a key role on the overall catalytic performances in terms of activity and selectivity (i. e., in their ability to obtain the highest bio‐oil fraction with the lowest oxygen content), and also importantly, stability. Detailed post‐mortem bulk and micro‐spectroscopic studies of the solid catalysts complement the catalytic testing. The obtained results point towards coke deposits as the main cause for catalyst deactivation. Details of the nature, formation and evolution of these coke deposits revealed essential insights, which serve to evaluate the design of catalysts for the ex‐situ CFP of biomass. In particular the mesoporous catalysts are overall better preserved with increasing time‐on‐stream and deactivate later than their microporous counterparts, which suffer from pore blockage. Likewise, it was seen that ZrO2‐promotion contributed positively in the prevention against deactivation by hard coke spreading, thanks to its enhanced Lewis acidity. The zeolite's crystal size is another important characteristic to combine the different components within catalyst bodies, ensuring the proper interaction between zeolite, promoter and binder. This is illustrated by the nanocrystalline ZrO2/n‐ZSM‐5‐ATP material, which shows the best catalytic performance. [ABSTRACT FROM AUTHOR]

The choice of support type has a profound influence on catalyst performance in liquid phase hydrogenation reactions, including the catalytic hydrogenation of biomass‐derived levulinic acid (LA) to γ‐valerolactone (GVL). Catalytic performance, including stability, of three Ru/TiO2 catalysts, having a similar mean Ru metal nanoparticle size but supported on three types of TiO2, namely P25, rutile and anatase, is evaluated by multiple reuse under batch reactor conditions. T3he catalysts' physicochemical properties before and after recycling are characterized by XRD, STEM, TGA and FT‐IR after CO stepwise adsorption. The results show that the deactivation seen for (mixed) anatase‐supported catalysts in dioxane can be attributed to strong metal‐support interaction (SMSI) rather than coke formation or metal sintering, with the rutile‐based catalyst being more resistant against such support reduction. Notably, SMSI formation under the applied, relatively mild conditions only occurs in the presence of organic acids, such as LA or valeric acid. [ABSTRACT FROM AUTHOR]

Monometallic Pt and bimetallic Pt-Cu catalysts supported on Mg(Al)O mixed oxides, obtained by calcination of the corresponding layered double hydroxides (LDHs), were prepared and tested in the aqueous-phase reforming (APR) of glycerol. The effect of the Mg/Al ratio and calcination temperature of the LDH support, as well as the effect of varying Pt and Cu amounts on glycerol reforming, was investigated. The use of a basic support increases the selectivity to hydrogen and the use of a Pt-Cu bimetallic catalyst results in a decrease in alkane formation. The 0.9 wt. % Pt-0.4 wt. % Cu/Mg(Al)O_2.95 catalyst system with an Mg(Al)O mixed oxide support obtained by the calcination of the corresponding LDH material with Mg/Al ratio of 2.95 at 673 K, showed higher hydrogen selectivity (55.3 %) and lower methane production (1.9 %) after 5 h reaction than the benchmark Pt/Al2O3 catalyst (49.4 % and 5.6 %, respectively). Catalyst characterization by extended X-ray absorption fine structure (EXAFS) spectroscopy showed a bimetallic interaction between Pt and Cu. The bimetallic interaction is thought to be responsible for the lowered methane formation and, ultimately, the high hydrogen selectivity observed. [ABSTRACT FROM AUTHOR]

Transition metal ions and their complexes play a crucial role in homogeneous catalysis. These catalysts are pivotal for the production of, for example, fine chemicals and pharmaceuticals. Nevertheless, because of the homogeneous nature of these catalysts, their extraction and removal from the crude reaction mixture is cumbersome. Here, we propose an alternative approach where metal‐based homogeneous catalysts are generated electrochemically from a metallic anode (Cu), followed by their use without current, and finally again electrochemically deposited on the cathode. The generated Cu ions were used as catalysts in three different reactions of lauroyl peroxide: one ligand‐free (coupling with dienes), one without ligand but with a heteroatom containing substrate (coupling with toluidine and styrene) and one in the presence of 1,10‐phen as ligand (coupling with indazole). In the first two cases, performance of the electrochemically generated catalysts was similar to those reported in literature for classically prepared homogeneous catalysts, whereas in the last case a new reaction was observed. After reaction, the homogeneous copper catalyst could be efficiently removed electrochemically: 99% of the copper could be removed for the ligand‐free reaction, 97% for the amine coupling, whereas 89% of copper could be removed for the reaction containing N‐heterocycle and 1,10‐phenanthroline. [ABSTRACT FROM AUTHOR]