Thermally stable core–shell Ni/nanorod-CeO2@SiO2 catalyst for partial oxidation of methane at high temperatures

Abstract

During partial oxidation of methane (POM), the greatest challenge is to maintain the thermal stability of the catalyst at high temperatures. One of the most effective ways to improve thermal stability is to construct core–shell structure. Herein, using a microemulsion method, we synthesized a core–shell Ni/nanorod-CeO₂@SiO₂ catalyst, in which the Ni nanoparticles were supported on the CeO₂ nanorods and encapsulated by SiO₂ shells. Based on a series of characterizations, we found that the Ni particles are of nanosize (2.2 nm) and the thickness of the SiO₂ shell is about 8 nm in the core–shell catalyst. Moreover, the Ni/nanorod-CeO₂@SiO₂ catalyst can perfectly maintain rod-like structures of the CeO₂ support and enhance interaction between the metal Ni and CeO₂, significantly reducing the sintering of metal Ni particles at high temperatures. Therefore, the as-prepared Ni/nanorod-CeO₂@SiO₂ catalyst shows high catalytic activity and good thermal stability during the POM reaction.