纳米金催化剂的制备及其对肉桂醛选择性加氢的催化性能

以多壁碳纳米管和椰壳活性炭为载体,分别采用溶胶固载法和等体积浸渍法制备负载型纳米金催化剂。采用N_2吸附-脱附、XRD、TEM和XPS等对碳载体和纳米金催化剂样品进行表征,并研究纳米金催化剂在肉桂醛选择性加氢反应中的催化性能。结果表明,HNO_3-H_2SO_4预处理可以增加碳载体表面的含氧基团和含氮基团,在肉桂醛加氢反应中,溶胶固载法得到的更小尺寸的纳米金催化剂对C=C双键加氢选择性高,等体积浸渍法制备的纳米金催化剂对C=O双键加氢选择性高,椰壳活性炭为载体催化剂的C=C加氢催化活性优于多壁碳纳米管。

Preparation of nano Au supported carbon catalysts and their catalytic performance for selective hydrogenation of cinnamicaldehyde

Nano Au catalysts supported on multi wall carbon nanotubes(MWCNTs) and coconut activated carbon(CAC) were prepared by the solgel immobilization technology(SIT) and the impregnation method(IMP), respectively. Carbon supports and nano Au catalysts were characterized by N₂ adsorption desorption, XRD, TEM and XPS techniques. The catalytic performance of the catalysts for the selective hydrogenation of cinnamaldehyde was evaluated. The results showed that the concentrations of the oxygen containing groups and nitrogen containing groups on the surface of carbon supports were increased after pretreating with HNO₃H₂SO₄ mixed acids. The selectivity of the C and/or C=Obonds hydrogenated products in the selective hydrogenation of cinnamaldehyde was significantly affected by the carbon materials and the catalyst preparation methods. The catalyst prepared by the SIT method favored the selective hydrogenation of C=C bonds while the catalyst synthesized by the IMP method tended to the selective hydrogenation of C=O bonds. Moreover, Au/CAC catalyst exhibited clearly better catalytic performance than Au/MWCNTs catalyst for the selective hydrogenation of C=C bonds in the selective hydrogenation of cinnamaldehyde.