Synthesis of Pd/Fe3O4 Hybrid Nanocatalysts with Controllable Interface and Enhanced Catalytic Activities for CO Oxidation

Palladium is an important catalyst for many industrial processes and chemical reactions. The conjunction of Pd and a metal oxide is of particular interest for improving catalytic performance in heterogeneous catalysis. Here we report the synthesis of Pd/Fe3O4 hybrid nanoparticles with controllable interface and the evaluation of their catalytic activities for CO oxidation. The synthesis involves a seed-mediated process in which Pd nanoparticles serve as seeds, followed by the deposition of the Fe3O4 layer in the solution phase. The adhesion of the oxide layer to the metal surface is through the reduced form of Fe. Upon thermal annealing, the Fe3O4 layer evolved from complete to partial coverage on the Pd core surface. This process is accompanied by increased crystallinity of Fe3O4. The resultant Pd Fe3O4 nanoparticles with a partial Fe3O4 shell significantly lower the light-off temperature of CO oxidation.