Ni/Ti3C2(MXene)催化剂制备及催化肉桂醛选择加氢性能

Preparation of Ni/Ti3C2 (MXene) catalyst and its catalytic performance for selective hydrogenation of cinnamaldehyde

摘要:

以氢氟酸为蚀刻剂，Ti3AlC2为原料制备的多层Ti3C2(MXene)为载体，采用KBH4还原法制备Ni负载量（Ni在催化剂中的质量分数，全文同）5%~20%的Ni/Ti3C2，通过XRD、FTIR、SEM、N2吸附-脱附、NH3-TPD等对Ni/Ti3C2结构组成、形貌特征和表面性质进行了表征，考察不同Ni负载量的Ni/Ti3C2催化肉桂醛选择加氢的催化性能。结果表明，Ni负载量为10%的10Ni/Ti3C2具有最佳的催化性能，其Ni金属颗粒均匀负载在Ti3C2表面，层状结构清晰，比表面积为9.6 m2/g，具有最小的金属Ni平均粒径（43.59 nm）和最高的分散度（0.21%）；随着Ni负载量在5%~20%范围增加，Ni/Ti3C2的比表面积和酸位点强度逐渐增加，表面酸性位点种类变化不大，10Ni/Ti3C2具有强Lewis酸位点（NH3脱附峰在511 ℃左右），热稳定性较好。在肉桂醛1.0 g、反应H2压力2.0 MPa、30 mL异丙醇作溶剂、反应温度120 ℃的条件下，0.5 g的10Ni/Ti3C2催化肉桂醛选择加氢反应3 h，肉桂醛转化率和苯丙醇选择性分别是100%和99.29%；在5次循环使用中，10Ni/Ti3C2表现较高的催化稳定性，肉桂醛转化率100%，苯丙醇选择性99.29%~92.07%。

Abstract:

Multilayer Ti3C2(MXene) as a carrier was prepared using hydrofluoric acid as an etchant and Ti3AlC2 as raw material, Ni/Ti3C2 with Ni loading (mass fraction of Ni in the catalyst, same as the whole text) of 5%~20% was prepared by a KBH4 reduction method. The structural composition, morphological features and surface properties of Ni/Ti3C2 were characterized by XRD, FTIR, SEM, N2 adsorption-desorption, NH3-TPD, etc, and the catalytic performance of Ni/Ti3C2 for selective hydrogenation of cinnamaldehyde with different Ni loadings was investigated. The results showed that 10Ni/Ti3C2 with 10% Ni loading exhibited the best catalytic performance, and its Ni metal particles uniformly loaded on the surface of Ti3C2 with a well-defined layer structure and a specific surface area of 9.6 m2/g, exhibited the smallest average metallic Ni particle size (43.59 nm) and the highest dispersion (0.21%); The specific surface area and acid site strength of Ni/Ti3C2 increased gradually with increasing Ni loading in the range of 5% to 20%, with little change in the types of acid sites on the surface, 10Ni/Ti3C2 exhibited strong Lewis acid sites (NH3 desorption peak at approximately 511 °C) and good thermal stability. 0.5 g of 10Ni/Ti3C2 for selective hydrogenation of cinnamaldehyde reaction for 3 h under the conditions of 1.0 g cinnamaldehyde, reaction H2 pressure of 2.0 MPa, 30 mL of isopropanol as solvent, and reaction temperature of 120 °C, the cinnamaldehyde conversion and hydrocinnamyl alcohol selectivity were 100% and 99.29%, respectively. In five cycles, 10Ni/Ti3C2 showed high catalytic stability, 100% cinnamaldehyde conversion and 99.29%~92.07% hydrocinnamyl alcohol selectivity.