最近,具有中空核壳结构的纳米材料在催化领域中有着深入的研究和广泛的应用.在本文中,我们使用一种简单易行的方法合成了一种包裹钯纳米颗粒的中空介孔硅铝酸盐纳米球(简写为Pd@HMAN).首先,通过一种先原位合成钯纳米粒子再对其进行二氧化硅包裹的方法,在Brij56-环己烷-水的反相胶束中合成了具有核壳结构的包裹钯纳米颗粒的二氧化硅纳米球(简写为Pd@SiO2).然后,使用CTAB,Na2CO3和NaAlO2试剂,通过简单的碱性条件下刻蚀Pd@SiO2的过程,我们成功得到了具有多孔性能的中空核壳型Pd@HMAN纳米催化剂.由于硅铝酸盐外壳具有酸催化作用,并且内核钯纳米颗粒又是一种高活性的催化媒介,因此,这种复合的多功能纳米催化剂能够很好的应用于多步催化反应中.此外,通过一个简单的热处理的方法,能够缩小硅铝酸盐外壳上的孔道,我们发现这种孔道调节后的Pd@HMAN纳米催化剂在尺寸选择性氢化反应中有很好的应用前景.
In this work,yolk-shell structured Pd@hollow mesoporous aluminosilica nanospheres(designated as Pd@HMAN) have been successfully fabricated by a straightforward synthetic route.Core-shell Pd@SiO2 nanospheres were firstly obtained by silica coating of in-situ synthesized Pd nanoparticles in a Brij56-cyclohexane-water reverse micelle system.Simply by alkaline etching of as-prepared Pd@SiO2 core-shell nanospheres in the presence of CTAB,Na2CO3 and NaAlO2,Pd@HMAN particles with high porosity were obtained.As the mesoporous aluminosilica shells can serve as acid catalysts,and the Pd yolks can be applied to catalytic hydrogenation,the as-prepared Pd@HMAN can be used as a stable multifunctional catalyst for multistep reactions.Moreover,due to their adjustable pore parameters,Pd@HMAN after simple thermal treatment can be further applied in the size-selective hydrogenation.