Ionic liquid-trimetallic electrocatalytic system for C-O bond cleavage in lignin model compounds and lignin under ambient conditions

Electrocatalytic depolymerization of lignin into value-added chemicals offers a promising technique to make biorefining sustainable. Herein, we report a robust trimetallic PdNiBi electrocatalyst for reductive C-O bond cleavage of different lignin model dimers and oxidized lignin under mild conditions. The reduction reaction proceeds with complete substrate conversion and excellent yields toward monomers of phenols (80%–99%) and acetophenones (75%–96%) in the presence of an ionic liquid electrolyte with operational stability. Systematic experimental investigations together with density functional theory (DFT) calculations reveal that the outstanding performance of the catalyst results from the synergistic effect of the metal elements, which facilitates the easier formation of a key Cα radical intermediate and the facile desorption of the as-formed products at the electrode. The results open up new opportunities for lignin valorization through the green electrocatalytic approach.