Preparation of a finely dispersion nickel-based in-situ pyrolysis catalyst: Influence of lignocellulosic constituents

Abstract

Metal/biochar catalysts could be synthesized via directly subjecting biomass impregnated with metal salts to pyrolysis. The properties of biochar are intricately linked to the inherent composition of the raw material, which in turn could influence the degree of metal dispersion and its catalytic impact. The poplar sawdust and its fractioned proportion was employed for the preparation of Ni-based biochar catalysts. The work mainly focuses on the impact of lignocellulosic material with diverse compositions on the dispersion of nickel particles during the calcination-pyrolysis co-process. Given that cellulose and holocellulose constituted the majority of the material, the matching catalyst support may encourage the migration of nickel species to produce substantial amounts of particles, perhaps as a result of several reactions such as dehydration and aromatization. In contrast, the utilization of sawdust as a support demonstrated a remarkable effect in dispersing nickel particles, nickel particle size and H₂ uptake were 7.0 nm and 19.8 μmol/g, respectively, while also displaying exceptional catalytic activity in the hydrogenation of vanillin, with the maximum conversion and 2-methoxy-4-methylphenol (MMP) yield of 99.7 % and 69.0 %. It has been determined that the presence of lignin in the system has a beneficial impact on the dispersion of nickel and its catalytic activity.