Tuning the Reduction Degree of Ni-Based Catalysts for Selective Hydrogenation of Furfural

The selective hydrogenation of biomass-derived compounds is pivotal for the synthesis of high-value-added chemicals. In this study, Ni2Al-LDO（layered double oxide） metal oxide catalyst featuring highly dispersed surface NiO was synthesized via a structural topological transformation using layered double hydroxides. The catalyst exhibited excellent performance in the hydrogenation of furfural, achieving 91.42% yield of furfuryl alcohol (FOL) at 160 °C and 1.4 MPa H2. Gradual reduction of Ni2Al-LDO produced Ni/NiO mixtures, enabling tunable shift from FOL to tetrahydrofurfuryl alcohol (HFOL) as the NiO content decreased and the Ni content increased. After a two-hour reduction at 700 °C, the HFOL yield reached 93.95%. CO2-TPD, NH3-TPD, and FT-IR measurements revealed that variations in reduction degree on nickel influenced the adsorption behavior of furfural. NiO species could only adsorb the C=O group of furfural, whereas the flat adsorption mode on the metallic Ni surface facilitated the simultaneous adsorption and activation of both the furan ring and the carbonyl group of furfural.

生物质衍生化合物的选择性加氢是合成高附加值化学品的关键技术路径。本研究通过层状双氢氧化物的结构拓扑转变，合成了表面负载高度分散NiO的Ni₂Al-LDO（层状双金属氧化物，layered double oxide）金属氧化物催化剂。该催化剂在糠醛加氢反应中表现出优异的催化性能：在160℃、1.4MPa氢气氛围下，糠醇（FOL）的收率可达91.42%。对Ni₂Al-LDO进行逐步还原可得到Ni/NiO混合体系，随着NiO含量降低、金属Ni占比提升，催化产物可从糠醇（FOL）向四氢糠醇（HFOL）实现定向调控。在700℃下还原2小时后，四氢糠醇（HFOL）的收率可达93.95%。通过CO₂-TPD（二氧化碳程序升温脱附）、NH₃-TPD（氨程序升温脱附）及FT-IR（傅里叶变换红外光谱）表征结果显示，镍基催化剂的还原程度变化会影响糠醛的吸附行为：NiO物种仅能吸附糠醛的C=O羰基基团，而金属Ni表面的平面吸附模式可同时实现糠醛呋喃环与羰基基团的吸附与活化。