A new approach to explore the catalytic depolymerization of lignin via samarium oxide

Rare earth catalysts have gained considerable attention in the catalytic depolymerization of lignin. However, their structure-performance relationship was rarely reported. This work demonstrated that the different morphologies of Sm2O3 exhibited remarkable structure-activity relationships in the catalytic oxidation of lignin. Four different morphologies of samarium oxides, namely rod-like, tube-like, octahedral, and multilayer were investigated. Rod-like Sm2O3 catalyst exhibited optimum activity in the oxidation of lignin model molecules and real lignin. The {222} crystal surface of the Sm2O3 catalyst was proved to play a key role. beta-O-4, C alpha-C beta, and Csp2-Csp2 chemical bonds in lignin were synchronously broken.