Lignin-first depolymerization of softwood over a NiCu/TiO2 catalyst for the sustainable production of dihydroconiferyl alcohol.

Reductive catalytic fractionation (RCF) has emerged as a promising biorefinery strategy for lignin valorization. However, the inherent structural complexity of lignin often results in low selectivity toward specific high-value products, limiting the economic viability of this process. Herein, we report a bimetallic NiCu/TiO2 catalyst that enables efficient RCF of Pinus sawdust, achieving exceptionally high selectivity (up to 88.07 %) toward the dihydroconiferyl alcohol (Pol-G). Mechanistic studies reveal that the synergistic effect of the NiCu alloy suppresses the elimination of Cγ-OH group in β-O-4' linkages, thereby steering the reaction pathway toward the formation of Pol-G. Notably, the fabricated catalyst demonstrates outstanding catalytic reusability when applied to both lignin model compounds and raw lignocelluloses, as well as good substrate universality. In addition, systematic investigation of key reaction parameters, including solvent, catalyst dosage, temperature, time, and H2 pressure, further elucidate how these conditions govern product distribution. Collectively, this work paves the way toward more economically viable and sustainable strategies for lignin valorization.