Rationalization of the catalytic performance of bimetallic Ni-Fe catalysts in selective hydrogenation reactions is based on the Ni and Fe distribution within the nanoparticles and at their surface. By applying a combination of element-specific and surface-specific characterization techniques (⁵⁷Fe Mössbauer spectroscopy, X-ray absorption spectroscopy, and low-energy ion scattering) to a series of Ni-Fe/SiO₂ catalysts differing by their Ni and Fe molar proportions, we showed that reduced Ni-Fe nanoparticles exhibit a gradient of Ni concentrations from a Ni-enriched core to Ni-depleted, Fe-enriched outer shells. A surface proportion of 35–45 Ni atom % showed the highest yield of furfuryl alcohol in liquid-phase hydroconversion of furfural. These results point to the need for Ni surface domains of limited size among Fe atoms to restrict the hydroconversion process to its first stage rather than to nominal compositions of the catalyst or to surface sites that would appear to be particularly selective per se.

双金属 Ni-Fe 催化剂在选择性加氢反应中的催化性能合理化是基于纳米颗粒内及其表面的 Ni 和 Fe 分布。通过将元素特异性和表面特异性表征技术（⁵⁷ Fe Mössbauer 光谱、X 射线吸收光谱和低能离子散射）组合应用于一系列 Ni-Fe/SiO ₂催化剂的 Ni 和 Fe 摩尔比例不同，我们发现还原的 Ni-Fe 纳米颗粒表现出从富 Ni 核到贫 Ni、富 Fe 外壳的 Ni 浓度梯度。35-45 Ni 原子% 的表面比例表明糠醛液相加氢转化中糠醇的收率最高。这些结果表明需要在 Fe 原子中具有有限尺寸的 Ni 表面域，以将加氢转化过程限制在其第一阶段，而不是限制在催化剂的标称组成或看起来特别具有选择性的表面位点。