Hydrodeoxygenation upgrading of bio-oil on Ni-based catalysts with low Ni loading

Selective Catalytic Transfer Hydrogenation of Lignin to Alkyl Guaiacols Over NiMo/Al‐MCM‐41

“…Acidic sites in these supports facilitate the adsorption and dissociation of oxygen-containing functional groups, promoting deoxygenation alongside hydrogenation over metal dopants (such as Ni and noble metals). [21] Although catalyst acidity is important for lignin conversion to monomers, it can also drive the repolymerization of partially degraded (unsaturated) lignin fragments with smaller molecules to form undesired chars. [22] The number and activity of acid and metal sites must be carefully balanced to optimize HDO.…”

“…Earth-abundant metals are therefore sought as substitutes for biomass valorization, notably Ni, Co, Mo, Fe, Cu, and Zn. [21,26,37] Ni is a popular choice for lignin depolymerization due to its modest price and good performance in hydrotreatments (including hydrogenation, hydrogenolysis, and HDO). [38] Huang et al reported low-temperature lignin depolymerization over Ni catalysts using formic acid as an insitu hydrogen source to obtain low-molecular-weight products ( � 2000 g mol À 1 ) and increased oil yields (85-95 wt%).…”

“…Metal oxides including Al 2 O 3 , CeO 2 , and NbOPO 4 are common as the former component, [19,20] although their modest specific surface areas and acidic properties leave significant scope for improvement. Acidic sites in these supports facilitate the adsorption and dissociation of oxygen‐containing functional groups, promoting deoxygenation alongside hydrogenation over metal dopants (such as Ni and noble metals) [21] . Although catalyst acidity is important for lignin conversion to monomers, it can also drive the repolymerization of partially degraded (unsaturated) lignin fragments with smaller molecules to form undesired chars [22] .…”

“…Unfortunately, their scarcity and consequent high cost limits their likely commercial use in the emergent latter application. Earth‐abundant metals are therefore sought as substitutes for biomass valorization, notably Ni, Co, Mo, Fe, Cu, and Zn [21,26,37] . Ni is a popular choice for lignin depolymerization due to its modest price and good performance in hydrotreatments (including hydrogenation, hydrogenolysis, and HDO) [38] .…”

Bio-oil Upgrading via Ether Extraction, Looped-Oxide Catalytic Deoxygenation, and Mild Electrocatalytic Hydrogenation Techniques

“…Thus, great attention should be paid to the production of fuels from biomass feedstocks . However, the bio-oil obtained from the fast biomass pyrolysis (primary bio-oil), which is the intermediate product of the biofuel and chemical production, has the disadvantages of thermal instability, low heating value, high corrosiveness, high water content, high oxygen content, and low hydrogen content compared to mature fuels, such as gasoline and diesel. − Hence, primary bio-oil cannot be directly used because its overall quality needs to be significantly enhanced via additional treatments (bio-oil upgrading). , …”