Highly stable Co@BC catalysts encapsulated in biochar for efficient lignin hydrogenolysis to valuable monophenols

The development and utilization of renewable lignin from industrial crops to produce high-value bio-based chemicals and fuels is of great significance in reducing dependence on fossil resources and promoting green chemistry. However, conventional metal-supported catalysts often suffer from poor metal dispersion and particle agglomeration during lignin conversion, resulting in insufficient catalytic activity. To address these challenges, a novel biochar-encapsulated cobalt catalyst (Co@BC) was developed in this study for efficient lignin hydrogenolysis. The catalyst formed a unique thin carbon layer structure by encapsulating cobalt nanoparticles in biochar, which enhanced metal dispersion and prevented particle agglomeration. The performance of the catalysts was systematically evaluated at different calcination temperatures. Co@BC-650 showed the best results with a lignin liquefaction degree of 79.7 % and a monophenol yield of 19.1 wt%. This yield was significantly higher than that of the supported Co/BC-650 catalyst, which only reached 15.4 wt%. The thin carbon layer not only facilitated the reduction of cobalt species at 650 °C, but also provided antioxidant protection and maintained the stability of metallic cobalt, which was essential for H₂ adsorption and activation. In addition, Co@BC-650 exhibited excellent stability with little loss of activity after 3 cycles. This study provides an efficient and sustainable method for the selective production of monophenols from renewable lignin from industrial crops, which has the potential to be widely applied for biomass conversion and large-scale sustainable chemical production.