Abstract:

NiZr/Ti₃C₂ (Ni mass fraction 10%) catalysts with a Zr supporting amount of 5%—15% were prepared by a KBH₄ reduction method, and the effect of the Zr addition on the structure of the Ni/Ti₃C₂ catalyst and its catalytic activities for cinnamaldehyde selective hydrogenation were investigated by characterization combined with cinnamaldehyde selective hydrogenation on the catalysts. The results showed that with the increase in the Zr supporting amount, the agglomeration of Ni metal particles decreased, and the Ti₃C₂ support of the catalysts exhibited a well-defined layer structure. The specific surface area of the catalysts increased first and then decreased, while the types of surface acid sites changed little. Among them, the 10Ni10Zr/Ti₃C₂ catalyst exhibited a smallest average Ni active metal particle size and a maximum specific surface area of 132.8m²/g, as well as the Brønsted acid strength and stability was slightly enhanced, and the Lewis acid strength and stability was decreased, showing the optimal catalytic activity. Under the same reaction conditions, on the 10Ni10Zr/Ti₃C₂ catalysts, the cinnamaldehyde conversion was increased from 92.57% to 98.34%, the hydrocinnamaldehyde selectivity was increased from 91.15% to 94.81%, the hydrocinnamaldehyde yield was increased by 8.86% compared with the 10Ni/Ti₃C₂ catalyst. Furthermore, the 10Ni10Zr/Ti₃C₂ exhibited a high stability in cycling experiments.

Key words: NiZr/Ti₃C₂, catalysis, cinnamaldehyde, selective hydrogenation, KBH₄ reduction

摘要：

采用KBH₄还原法制备了Zr负载量为5%～15%（质量分数）的NiZr/Ti₃C₂（MXene）催化剂，通过结构表征结合催化剂上肉桂醛选择加氢活性测试，研究添加Zr对Ni/Ti₃C₂催化剂结构及其催化肉桂醛选择加氢的影响。结果表明，随着Zr负载量的增加，能减少Ni金属颗粒团聚，载体Ti₃C₂的层状结构清晰，催化剂比表面积先增加后减小，表面酸性位点的种类变化不大，其中，10Ni10Zr/Ti₃C₂催化剂的活性金属Ni的平均粒径最小且具有最大比表面积（132.8m²/g），其Brønsted酸强度和稳定性略微增强，Lewis酸强度和稳定性降低，表现出最佳催化性能；在同一反应条件下，与10Ni/Ti₃C₂催化剂相比，10Ni10Zr/Ti₃C₂催化剂上肉桂醛的转化率从92.57%提高到98.34%，苯丙醛的选择性从91.15%增加到94.81%，苯丙醛收率提高了8.86%，在循环实验中表现出较高的稳定性。

关键词: NiZr/Ti₃C₂, 催化, 肉桂醛, 选择加氢, KBH₄还原