Aqueous-Phase Glycerol Conversion over Ni-Based Catalysts Synthesized by Nanocasting

Abstract

A morphological strategy consisting of nanocasting synthesis of nickel aluminate spinel precursor was addressed. Two nanocasted catalysts were synthesized involving different template‑removal procedures (i.e., Teflon-assisted calcination vs. NaOH washing) for spinel recovery. As a reference, spinel NiAl2O4 supported by SBA-15 and bare nickel aluminate spinel were selected. The obtained solids were characterized in detail, examining their textural, acid–base, structural and compositional characteristics, either in the calcined or reduced forms. The as-obtained catalysts’ performance was evaluated in the aqueous-phase reforming of glycerol at 235 °C and 35 bar. Exhausted samples were also characterized to enlighten changes in catalyst properties during the aqueous-phase reaction. NiAl/SBA-15 and NiAl-NCF catalyst showed very poor catalytic performance for the glycerol transformation. NiAl-NCN catalyst presented improved activity with respect to NiAl, with a 20% higher hydrogen production rate but, as a drawback, higher methane formation for a whole range of glycerol conversions. Exhausted catalyst indicated nickel oxidized in liquid phase reaction.

New Trends in Catalytic Conversion of Glycerol

“…Meanwhile, physical-chemical properties and catalytic performance of the spent catalysts were also characterized and tested. It proved that nickel was oxidized in the liquid phase reforming [8]. Besides reforming, glycerol can also act as a green hydrogen source in catalytic transfer hydrogenation reactions.…”

“…The power rate law model was found to be the most suitable for total oxidation, and the Eley-Rideal-type mechanism was the best for the description of the CO 2 methanation reaction [7]. Ayastuy and co-workers studied the aqueous-phase reforming of glycerol over NiAl catalyst [8]. Two different template removal methods were used in the synthesis of the catalysts.…”