激光溅射法制备Pt/CNTs催化剂用于邻氯硝基苯的液相加氢反应

采用激光溅射法制备了碳纳米管负载铂(Pt/CNTs)催化剂, 并利用透射电子显微镜(TEM)、X射线能量散射谱(EDS)、X射线衍射(XRD)、X射线光电子能谱(XPS)等表征手段研究了Pt粒子在碳纳米管表面存在的状态、组成、结构等性质. 讨论了Pt/CNTs催化剂的不同制备条件对催化剂结构的影响, 并考察了催化剂对邻氯硝基苯液相加氢合成邻氯苯胺反应的加氢性能. 研究结果表明, 在激光电压为250 V, 绝对压力为300 Pa, 载体温度为25 ℃条件下制备的Pt/CNTs催化剂, 在不加脱卤抑制剂, 反应温度为60 ℃和氢气压力为1.0 MPa的条件下, 邻氯硝基苯转化率可以达到99.7%以上, 邻氯苯胺选择性可达到98.2%以上, 表现出较高的加氢性能和抑制脱卤性能.

Hydrogenation of o-chloronitrobenzene over CNTs Supported Pt Catalyst Obtained by Laser Vaporization of Bulk Metal

Pt nano clusters were produced by the laser vaporization of bulk metal and were deposited on the surface of carbon nanotubes (CNTs) to produce carbon nanotubes supported Pt catalyst (Pt/CNTs). Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) showed that Pt nanoparticles had a narrow size distribution and the Pt content was connected with the preparation condition. X-ray diffraction (XRD) analysis showed that the Pt/CNTs had crystalloid structure which related to the catalytic performance. X-ray photoelectron spectroscopy (XPS) was used to measure core level binding energy shifts of Pt 4f7/2 and Pt 4f5/2. Its catalytic performance was evaluated by liquid-phase hydrogenation of o-chloronitrobenzene (o-CNB). The results showed that the Pt/CNTs catalyst exhibited higher conversion and selectivity. The most favorable preparation condition was obtained as follows: T=25 ℃, V=250 V, and p=300 Pa. It was found that the highest conversion of o-chloronitrobenzene could reach 99.7% while the selectivity to o-chloroaniline could reach 98.2% in alcohol at 60 ℃ under 1.0 MPa of hydrogen, showing good potential application.