Nickel/USY Catalyst Derived from a Layered Double Hydroxide/Zeolite Hybrid Structure with a High Hydrogenation Efficiency

It is important and challenging in heterogeneous catalysis to prepare catalysts with highly dispersed metal nanoparticles that have a high activity. Herein, a new Ni/USY catalyst derived from a core–shell NiAl-LDHs/USY hybrid material has been prepared by the in situ growth of a layered double hydroxides (LDHs) precursor on the surface of USY zeolite crystals. Under the appropriate conditions, the adscititious Ni source interacted chemoselectively with Al species dissolved from the zeolite framework to form a LDHs structure anchored robustly on the surface of zeolite crystals. The dealumination of the low-silica zeolite and the immobilization of Ni metal species were realized simultaneously in this one-pot synthesis to afford hierarchical NiAl-LDHs/USY hybrid composites. The Ni^II species in these hybrid composites were reduced readily at much lower temperatures than that of bulk NiAl-LDH, which gave rise to highly dispersed Ni nanoparticles. Meanwhile, the resultant material possessed an excellent mesoporous structure and a high surface area inherited from the USY structure, which led to an excellent hydrogenation rate and activity for the conversion of m-nitroaniline to m-phenylenediamine. This unique method could be a promising and general strategy to fabricate desirable hybrid materials for redox catalysis in particular for supported transition metals with similar characteristics to Ni.