Direct electrocatalytic depolymerization of lignin using a thermally stable organic salt electrolyte: performance and mechanistic insights.

Electrochemical depolymerization of lignin to produce low molecular weight aromatic compounds is characterized by mild conditions and low carbon emissions. However, using non-metallic catalysts for this process faces challenges in terms of selectivity and activity. This study found that high-melting-point organic salts - tetra-n-butyl tetrafluoroborate (TBABF), can function simultaneously as a catalyst and oxidant at room temperature and in air, effectively catalyzing the CO bond cleavage in lignin. The conversion rate of lignin from corn stalks was 86.95 %, with the total yield of aromatic compounds reaching 11.2 %. Mechanism studies revealed that the TBA cation radicals formed under suitable electrolysis conditions by TBABF are crucial for the activation of lignin substrates, while superoxide anions play a key role in the electrocatalytic depolymerization process. Additionally, TBABF acts as an electrolyte, enhancing the conductivity of the reaction system. This study provides new insights into the efficient electrochemical depolymerization of lignin using non-metallic compounds.