Impact of Second Metal (Cu, Co) on Catalytic Performance of Bimetallic Ni‐Based Catalyst for Phenol HDO

The conversion of biomass to renewable liquid fuels has received considerable attention for partly replacing conventional fuels and environmental concern. Converting biomass to liquid fuels (called bio-oil) via fast pyrolysis or hydrothermal treatment helps to increase volumetric and energy density and also to reduce transportation costs. However, the direct use of bio-oil for combustion engine/turbine has some implications because of different properties of bio-oil compared with conventional fossil fuels. More than 200 compounds in bio-oils are known, having various types of functional groups with specific chemistry. Furthermore, water accounts for 15-30 wt%. Therefore, upgrading of bio-oil is necessary to improve its properties and to make it suitable for further use. Among the available upgrading strategies, hydrodeoxygenation (HDO) is considered as interesting new technology. The development of suitable catalysts for this process is challenging up to now due to high coke formation and rapid deactivation at hydrothermal condition. Many researchers have applied conventional catalysts such as hydrodesulfurization (HDS) catalysts (CoMo/Al2O3, NiMo/Al2O3) and hydrotreating catalyst based on supported noble metal such as Pt, Pd or Ru). However, the first class of catalysts showed low activity and partly deactivation due to large water content in bio-oil. The latter class of catalysts presented high activity and stability, but their application is limited due to high costs. Apart from that, non-noble metal supported catalysts, mostly based on Ni, have been reported. Although these catalysts were also active, coke deposition on the catalyst was still the problem.