Chemicals from Lignin: A Review of Catalytic Conversion Involving Hydrogen

Lignin is the most abundant biopolymer with aromatic building blocks and its valorization to sustainable chemicals and fuels has extremely great potential to reduce the excessive dependence on fossil resources, although such conversions remain challenging. The purpose of this Review is to present an insight into the catalytic conversion of lignin involving hydrogen, including reductive depolymerization and the hydrodeoxygenation of lignin‐derived monomers to arenes, cycloalkanes and phenols, with a main focus on the catalyst systems and reaction mechanisms. The roles of hydrogenation sites (Ru, Pt, Pd, Rh) and acid sites (Nb, Ti, Mo), as well as their interaction in selective hydrodeoxygenation reactions are emphasized. Furthermore, some inspirational strategies for the production of other value‐added chemicals are mentioned. Finally, some personal perspectives are provided to highlight the opportunities within this attractive field. Getting better with H: This Review presents an insight into the catalytic conversion of lignin involving hydrogen, including reductive depolymerization and hydrodeoxygenation of lignin‐derived monomers, with a focus on catalyst systems and reaction mechanisms. The roles of hydrogenation sites and acid sites, strategies for the production of other value‐added chemicals, and future opportunities within this attractive field are discussed.