羰基合成与选择氧化国家重点实验室（OSSO）知识库

The selective hydrogenolysis of biomass-derived xylitol to ethylene glycol and propylene glycol was carried out over non-noble Ni-decorated Cu-SiO₂ nanocatalysts with a wide range of Cu/Ni mass ratios and metal loadings in the presence of Ca(OH)₂. The NiCu-SiO₂ bimetallic catalysts showed much superior activities and selectivities to the target glycols relative to the monometallic Cu-SiO₂ and Ni-SiO₂ catalysts. Among them, 10Ni80Cu-SiO₂ catalyst (10/80 refers to the mass ratio of NiO and CuO) prepared by co-precipitation-gel method presented the highest activity and target glycols selectivity, and up to 81.0% combined glycol yield was attained at 473 K and 8 MPa H₂. Moreover, this catalyst exhibited greatly enhanced stability in repeated runs. Characterization of these catalysts by XRD, XPS, BET, N2O-chemisorption, H₂-TPR and TEM showed that the decoration of suitable amount of Ni into Cu-SiO₂ catalysts had favorable effects on Cu dispersion, catalyst reducibility and the formation of highly active Ni surface-enriched Cu-Ni alloy sites. The notably enhanced performances of the NiCu-SiO₂ bimetallic catalysts could be ascribed to their significantly promoted C-OH dehydrogenation and C=O hydrogenation activities and high resistance to sintering of the active sites, imposed by the structural and electronic effects of Ni. Clearly, these findings provide useful guidance for the design of more efficient and stable non-noble bimetallic nanocatalysts for upgrading biomass-derived platform compounds particularly via hydrogenation/hydrogenolysis reactions.