Enhancing the Activity and Stability for Methane Dry Reforming over a Ni/CeO 2 Catalyst by a Comodification Strategy Using Silicon and Cobalt

Dry reforming of methane (DRM) converts greenhouse gases (CH 4 /CO 2 ) into H 2 /CO, which can be utilized for subsequent energy applications. To achieve high activity with nickel catalysts, the reaction temperature tends to exceed 800 °C, posing a severe challenge to the long-term stability of the catalysts. In this study, we prepared a novel nickel-cobalt bimetallic catalyst supported on silicon-modified CeO 2 . The representative Ni–Co/0.5SiCe catalyst exhibited enhanced CH 4 and CO 2 conversions of 71% and 80%, respectively, and practically remained stable for at least 50 h at 700 °C. The silicon reduced the CeO 2 crystallite size, enhancing the dispersion of nickel particles, and thereby improving CH 4 adsorption. The silicon modification increased the oxygen vacancies in CeO 2, providing pathways for reactive oxygen species to eliminate coke. The cobalt formed a stable Ni–O–Co structure with nickel particles. Cobalt oxides increased the electron density of the nickel catalyst, thereby weakening the strength of the C═O bond and thus promoting CO 2 adsorption. This made coke nucleation more difficult and altered the type of coke. Furthermore, the enhanced Ni–CeO 2 interaction and stable Ni–O–Co structure inhibited the sintering of nickel particles, thereby enhancing catalyst stability. This study offers new insights into the design of efficient Ni/CeO 2 -based catalysts for the DRM reaction.