Synthesis driven properties of Ru-Pd nanoalloy for catalytic hydrogenation of levulinic acid with formic acid as hydrogen source in aqueous media

The catalytic hydrogenation of the levulinic acid key platform molecule into γ-valerolactone using formic acid as bio-derived internal hydrogen source is considered as one of the pivotal reactions to convert sustainably lignocellulosic-based biomass into renewable added value chemicals. In this work we present the influence of both the composition and the synthesis methodology on the catalytic activity and properties of Ru-Pd bimetallic catalysts supported on activated charcoal, and particulary the conditions for nano-alloy formation. The Ru-Pd alloy shows high activity in formic acid decomposition and subsequent hydrogenation of levulinic acid in water solvent. The Ru-rich bimetallic catalyst prepared by co-impregnation with final high temperature reduction at 500◦C gave the highest γ-valerolactone yield, thanks to rearrangement and migration of Pd allowing for the formation of the Ru-Pd alloy with isolated (diluted) Pd atoms, and to stabilization of small particle sizes (1.3 nm) which showed high activity in the reaction.</p

Impact of Zr Incorporation into the Ni/AlSBA-15 Catalyst on Its Activity in Cellulose Conversion to Hydrogen-Rich Gas

This work focused on the investigation of the effect of zirconium incorporation into the structure of the Ni/AlSBA-15 catalyst on its performance in high-temperature conversion of cellulose (the main component of lignocellulosic feedstock) to hydrogen-rich gas. The modified supports were prepared by direct incorporation of zirconium and impregnation methods. The obtained results exhibited that introduction of zirconium into the structure of Ni/AlSBA-15 allowed for a considerable increase in the amount of hydrogen produced in the studied process in comparison to unmodified Ni/AlSBA-15 material. The characterization of physicochemical properties of the investigated materials (X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, time-of-flight secondary ion mass spectrometry, temperature-programmed reduction, temperature-programmed desorption of ammonia, etc.) showed that the preparation of mesoporous Ni/ZrAlSBA-15 with the use of the direct synthesis method led to obtaining the catalyst with a higher surface area and pore volume and smaller crystallites of an active phase in comparison to the material containing nickel supported on ZrAlSBA-15 with zirconium introduced by impregnation. Despite that the mesoporous catalyst prepared by impregnation possessed higher acidity, its structure underwent partial collapse during the preparation procedure