Highly efficient sea urchin-like N-doped CuCo bimetallic catalyst for selective cleavage of α-O-4 linkage in lignin

Refining lignin and its derivatives into biofuels and fine chemicals via catalytic transfer hydrogenation (CTH) has gained significant attention for its potential in utilizing renewable resources and reducing fossil fuel dependence. Herein, a series of bimetallic Cu-Co catalysts with varying metal ratios are synthesized via a facile hydrothermal method and successfully applied in the efficient CTH of the α-O−4 model compound benzyl phenyl ether (BPE) and corncob lignin. Cu 0.5 Co 1 @CN has the best performance among catalysts with different CuCo ratios due to the formation of the CuCo 2 O 4 phase which provides more acid sites and hydrogen adsorption/desorption sites. Under the reaction conditions of 190 °C in isopropanol, the Cu 0.5 Co 1 @CN catalyst achieves the complete conversion of BPE to cyclohexanol and toluene, and demonstrates excellent CTH performance towards other α-O−4 and β-O−4 model compounds. This catalyst simultaneously enables the demethoxylation and hydrogenation of phenolic compounds like guaiacol. Furthermore, Cu 0.5 Co 1 @CN efficiently converts corncob lignin, producing a high proportion of phenolic compounds in the resulting liquid (88.26%), while preventing the aromatic hydrocarbons from being hydrogenated. Overall, this work provides a novel and effective strategy for transforming lignin into high-value products.