Lignin-tailored synergistic catalyst with cobalt single-atom and zinc clusters dual-site for conversion of hemicellulose to lactic acid

A synergistic catalyst was prepared on lignin-derived carbon via two-step strategy. • The catalyst achieved an exceptional lactic acid yield of 58.91% from xylan. • The catalyst demonstrated remarkable versatility across diverse biomass-derived sugars. • High recyclability was realized attributable to Co–N 4 /Zn AC configuration. Hydrothermal catalysis offers a sustainable route for lignocellulosic valorization, while conventional catalysts often necessitate demanding conditions and efficient hemicellulose conversion remains challenging. Herein, a nitrogen-doped lignin-derived carbon-based synergistic catalyst, embedding cobalt single-atom and zinc atomic clusters (Co SAC -Zn AC @LCN), was constructed via a pre-coordination and pyrolysis two-step coupled strategy for one-pot conversion of hemicellulose to lactic acid (LaA). Characterizations revealed well-dispersed and spatially proximate Co single-atom and Zn clusters anchored on stacked two-dimensional carbon–nitrogen nanosheets. The strong synergistic interaction between Co single-atom and Zn clusters enhanced Lewis acidity and further facilitated C C bond cleavage and intermediate rearrangement. Co SAC -Zn AC @LCN exhibited a mesoporous structure with a high surface area (140.61 m 2 /g) and elevated carbon defects, promoting reactant diffusion and adsorption. Under optimized conditions (240 °C, 1 h), the catalyst achieved 58.9% LaA yield and 113.7 h −1 TOF from xylan and maintained over 42% yield across various biomass-derived sugars, demonstrating its remarkable catalytic performance and universality. Owing to the stable Co–N 4 /Zn AC configuration, it retained over 56% LaA yield after six cycles. This work provides a general strategy to design atomic-scale synergistic catalysts from biomass carbon for efficient lignocellulosic conversion to high-value chemicals. A nitrogen-doped carbon catalyst embedded with Co single-atom and Zn atomic clusters was constructed leveraging a lignin-derived framework. The strong synergistic interaction between Co single-atom and Zn clusters enhanced Lewis acidity and facilitated the efficiently conversion of hemicellulose to lactic acid. Owing to the stable Co–N 4 /Zn AC configuration, it retains excellent cycling stability. Download: Download high-res image (145KB) Download: Download full-size image