No abstract

The development of non-noble metal-based catalysts for the hydrodeoxygenation (HDO) upgrading of biomass pyrolysis oils is crucial for realizing the cost-effective biofuel production. In this paper, we report on the enhanced HDO activity of the rhenium-promoted nickel catalysts (Ni-Re) for the HDO of a pyrolysis oil model compound, guaiacol. The catalyst screening studies revealed that the Ni-Re displayed a considerably higher HDO activity than other monometallic (Ni, Re, Cu, Co) and bimetallic catalysts (Cu-Re, Co-Re), highlighting its unique catalytic property. In order to optimize the catalytic activity and reveal the structure-activity relationship of the Ni-Re catalysts, the effects of the Ni/Re ratio and type of support (SiO 2 , TiO 2 , and ZrO 2 ) on the catalyst structure and HDO activity were investigated in detail. The results showed that the addition of rhenium to nickel altered both geometric and electronic structures of nickel significantly. The Ni-Re/SiO 2 catalyst with a Ni/Re ratio of 0.315 achieved~95% yield of the desired deoxygenation product, cyclohexane, at 523 K and 30 bar-H 2 after 5 hours. Novelty StatementThe upgrading of biomass pyrolysis oils to hydrocarbon fuels oftentimes requires the use of noble metal catalysts and harsh reaction conditions (e.g., high H 2 pressure), all of which greatly increase the process cost. In this work, a highly active and nonprecious metal-based catalyst, bimetallic Ni-Re/SiO 2 , is developed for the cost-effective upgrading of biomass-derived phenols to deoxygenated hydrocarbon fuels at low temperature and low pressure.

No abstract

No abstract

The pretreatment of cellulose using the dissolution/regeneration process in ionic liquid and deep eutectic solvents leads to substantially higher hydrolysis efficiency than the conventional ball-milling pretreatment.

The efficient hydrolysis of cellulose into its monomer unit such as glucose or valuable cello-oligosaccharides is the critical step for the cost-effective production of biofuels and biochemicals. However, the current cellulose hydrolysis process involves high energy-demanding pretreatment (e.g., ball-milling) and long reaction times (>24h). Herein, we investigated the feasibility of the dissolution/regeneration (DR) of cellulose in ionic liquids (ILs) and deep eutectic solvent (DES) as an alternative to ball-milling pretreatment for the effective hydrolysis of cellulose. Because chlorine-based solvents are reported to be most active for biomass pretreatment, [EMIM]Cl and [DMIM]DMP were selected as the IL molecules, and choline chloride-lactic acid was selected as the DES molecule. The level of the crystallinity reduction of the regenerated cellulose were analyzed by the XRD and SEM measurements. The hydrolysis kinetics of the regenerated cellulose from ILs and DES were examined at 150 °C using sulfonated carbon catalysts and compared with the ball-milled cellulose. Overall, the cellulose pretreatment using the ILs and the DES had similar or superior kinetics for cellulose hydrolysis to the conventional ball milling treatment, suggesting a possibility to replace the current high energy-demanding ball-milling process with the energy-saving DR process. In addition, the utilization of supercritical carbon dioxide-induced carbonic acid as an in-situ acid catalyst for the enhanced hydrolysis of cellulose was presented for the first time.