Silica-encapsulated bimetallic Co-Ni nanoparticles as novel catalysts for partial oxidation of methane to syngas

The bimetallic Co-Ni nanoparticles that are encapsulated by porous silica shell were synthesized for partial oxidation of methane to syngas. By carefully tuning the Co/Ni ratios of core-shell structured catalysts, the catalytic activity can be efficiently modified: CoNi2@SiO2>Ni@SiO2>CoNi@SiO2>Co2Ni@SiO2>>Co@SiO2. The CoNi2@SiO2 catalyst outperforms the other counterparts at a reaction temperature of 700 degrees C. The proper alloying of Co and Ni metals cannot only enhance catalyst activity but also suppress carbon deposition during the reaction. The encapsulation of the nanoparticles of Co-Ni alloy can also effectively prevent aggregation of core alloy nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.