Structurally Confined Ni with Oxygen-Deficient CeO₂ for Efficient Self-Transfer Hydrogenolysis of Lignin into Jet...

Lignin catalytic hydrogenolysis offers a promising route to yield aromatic and alkane fuels for sustainable aviation. However, its widespread application is hindered by the reliance on high-pressure hydrogen and aggregation of metal catalysts during hydrogenolysis processes. Self-transfer hydrogenolysis is an attractive method to depolymerize without exogenous hydrogen, but suffers from low catalytic activity and poor stability. In this study, a nickel catalyst confined on cerium dioxide (CeO₂) nanocrystals with oxygen vacancy (O_V) is reported for efficient hydrogenolysis of both native and technique lignin into aviation fuel precursor under a nitrogen atmosphere. The O_V in CeO₂ acts as electron-deficient sites, promoting the reduction of neighboring Ni atoms to a lower valence state. These low-valent Ni species efficiently cleave C─O bonds in lignin, while the oxygen vacancies serve as anchoring sites to suppress aggregation of metallic Ni nanoparticles. The confined Ni/CeO₂ with oxygen vacancies exhibits top-level hydrogenolysis performance with an exceptional aromatic monomer yield of 42% from eucalyptus lignin and ≈20% from technical lignin, comparable to that of commercial noble metal catalysts. This work opens up new possibilities of designing efficient catalysts to depolymerize both raw wood powder and technical lignin toward aviation fuel precursor.