Cooperative catalysis over NiCoMoFeAlOx multimetal oxides: integration of Mo and Fe sites for selective hydrodeoxygenation of lignin to phenolic compounds

Lignin is the most abundant renewable organic aromatic compound carbon source in nature, and it is of great significance to convert it into high-value fine chemicals. However, achieving this goal requires regulating the selectivity of the lignin hydrodeoxygenation (HDO) reaction is crucial to breaking the competitive relationship between C–O bond cleavage and aromatic ring saturation. This study proposes oxygen-philic-hydrogen activation dual-functional site synergy strategy, using NiCoAl-LDH as the precursor, and constructing a NiCoMoFeAlO x multi-metal oxide catalyst by introducing Mo and Fe. Experiments and DFT calculations show that the catalyst achieves precise coupling of depolymerization and deoxygenation through a tandem synergy mechanism, the NiCo sites efficiently activate H 2 to supply active hydrogen, the oxygen-philic Mo sites and Fe selectively adsorb and cleave C–O bonds, and the intermetallic synergy effectively inhibits excessive hydrogenation of aromatic rings, directing the reaction path to phenolic products with retained aromatic rings. In the real lignin HDO reaction, the catalyst achieves a liquid yield as high as 78% and 64.9% selectivity for C 6+ cyclohexanol. This research provides a new paradigm for the rational design of multi-functional catalysts and the realization of directed conversion of lignin. Download: Download high-res image (244KB) Download: Download full-size image