高分散Pd/Ni-A-CA纳米催化剂催化喹啉加氢

High dispersion Pd/Ni-A-CA nanocatalysts for catalytic hydrogenation of quinoline

摘要:

以镍为金属节点，腺嘌呤和柠檬酸为有机配体，采用溶剂热法制备非晶态金属有机配合物Ni-A-CA。将PdCl2溶液浸渍于载体Ni-A-CA后用NaBH4还原制得高分散的Pd纳米粒子（Pd NPs）催化剂Pd/Ni-A-CA。通过XRD、TEM、XPS等对催化剂的结构、形貌以及组成进行表征分析。结果表明：Pd NPs高度分散在载体Ni-A-CA上，其粒径为2.2 ± 0.3 nm，且载体与Pd NPs之间存在强的相互作用，增强了催化剂的催化性能。在90 ℃，2 MPa H2条件下，负载量为3%（以Ni-A-CA的质量计，下同）Pd/Ni-A-CA催化剂催化喹啉加氢反应70 min，喹啉转化率为99%，生成1,2,3,4-四氢喹啉选择性大于99%。催化剂3% Pd/Ni-A-CA经过5次循环后，其催化性能基本保持不变。

Abstract:

The amorphous metal-organic compounds (Ni-A-CA) were prepared by combining nickel node with organic ligands (adenine (A) and citric acid (CA)) via solvothermal method. Then, highly dispersed Pd/Ni-A-CA catalysts developed were fabricated by dispersing PdCl2 on amorphous support and reducing PdCl2 solution via freshly prepared NaBH4. The microstructure, morphology, and compositions of the obtained Pd/Ni-A-CA catalysts were comprehensively investigated by XRD, FT-IR, TEM, and XPS, etc. The results showed that Pd NPs were in high dispersed state and Pd NPs size diameter was 2.2 ± 0.3 nm. Besides, there existed a strong interaction effect between Pd NPs and amorphous Ni-A-CA support. The optimal temperature and hydrogen pressure were 90 °C and 2 MPa H2, respectively. Under this condition, the conversion of quinoline and the selectivity of 1,2,3,4-tetrahydroquinoline were about 99% over 3% Pd/Ni-A-CA catalyst for 70 min reaction duration. Furthermore, the Pd/Ni-A-CA catalyst also exhibited good catalytic stability and catalytic performance basically kept unchanged after 5 cycles.