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

以镍(Ni)为金属节点,腺嘌呤(A)和柠檬酸(CA)为有机配体,采用溶剂热法制备了非晶态金属有机配合物Ni-A-CA。将Pd Cl2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SEM、TEM、XRD、FTIR、XPS、N2吸附-脱附对载体Ni-A-CA[n(Ni)∶n(A)∶n(CA)=2∶1∶1.5]和催化剂3%Pd/Ni-A-CA(3%为Pd的理论负载量,以Ni-A-CA的质量计,下同)进行了表征。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之间存在的强相互作用增强了催化剂的催化性能。在90℃、2 MPa H2条件下,3%Pd/Ni-A-CA催化喹啉加氢反应70 min,喹啉转化率为99.0%,生成1,2,3,4-四氢喹啉选择性>99%。

Amorphous metal-organic compound(Ni-A-CA)was firstly synthesized from solvothermal reaction of nickel(Ni),adenine(A)and citric acid(CA).Then,highly dispersed catalysts(Pd/Ni-A-CA)were prepared by dispersing PdCl_(2) on Ni-A-CA substrate and further reduction of PdCl_(2) solution via freshly prepared NaBH4.Substrate Ni-A-CA[n(Ni):n(A):n(CA)=2:1:1.5]and catalyst 3%Pd/Ni-A-CA(3%is the theoretical load of Pd,calculated by the mass of Ni-A-CA,the same below)were characterized by SEM,TEM,XRD,FTIR,XPS,N_(2) adsorption and desorption.The results showed that Pd NPs were highly dispersed on the surface of Ni-A-CA substrate with a particle size of(2.2±0.3)nm,and the catalytic performance of Pd/Ni-A-CA was enhanced by the strong interaction between the Pd NPs and the substrate.Under reaction temperature of 90 C,reaction pressure of 2 MPa H_(2),and rection time of 70 min,the catalyst 3%Pd/Ni-A-CA led to a conversion rate of quinoline and selectivity of 1,2,3,4-tetrahydroquinoline of 99.0%and>99%,respectively.