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

Abstract

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.

CO oxidation as a test reaction for strong metal–support interaction in nanostructured Pd/FeO powder catalysts

“…Other CO-oxidation studies on Pd/Fe systems like Pd/Fe 3 O 4 core-shell particles [12], Pd/␣-Fe 2 O 3 [13] or evaporated model system [14] showed moderate catalytic activity with T 50 values between 363 K [12] and 453 K [13] as well as a change of the crystal structure during reaction. The model system showed an E a of 136 kJ/mol, decreasing with increasing reduction temperature.…”

CuO Nanorods-Decorated Reduced Graphene Oxide Nanocatalysts for Catalytic Oxidation of CO

“…The catalytic oxidation of CO is one of the simplest and the most extensively investigated reactions in heterogeneous catalysis [1][2][3][4][5][6][7][8][9][10], and the catalytic oxidation of CO has become an important research topic over the past years. Up to now, many very effective noble metal catalysts, such as Pd [3,11], Au [4,12], Ru [13,14], and Pt [5,15] have been developed for this reaction. However, the poor stability and high cost limit the applications of these noble metal catalysts.…”

Strong metal–support interactions between palladium and iron oxide and their effect on CO oxidation

“…The studies range from probing single crystal surfaces as well as supported catalysts. Pd supported on iron oxide is investigated in several papers [19][20][21][22][23][24][25][26]. It was found that Pd supported on iron oxide is highly active in CO oxidation, at temperatures unusually low even for Pd.…”