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

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 (TBABF₄), 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 TBABF₄ are crucial for the activation of lignin substrates, while superoxide anions play a key role in the electrocatalytic depolymerization process. Additionally, TBABF₄ 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.