Synthesis of Pd/Fe ₃ O ₄ 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/Fe 3 O 4 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 Fe 3 O 4 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 Fe 3 O 4 layer evolved from complete to partial coverage on the Pd core surface. This process is accompanied by increased crystallinity of Fe 3 O 4 . The resultant Pd–Fe 3 O 4 nanoparticles with a partial Fe 3 O 4 shell significantly lower the light-off temperature of CO oxidation.