Gas-Phase Synthesis of Ni–CeO_<i>x</i> Hybrid Nanoparticles and Their Synergistic Catalysis for Simultaneous Reforming of Methane and Carbon Dioxide to Syngas

Abstract

We develop a new Ni–CeOx hybrid nanoparticle as a high-performance catalyst for dry reforming of methane with carbon dioxide (DRM) using a facile gas-phase synthetic approach. The crystallites of Ni and CeO2 were homogeneously self-assembled as a hybrid nanostructure, creating a large amount of Ni–Ce–O interface for a strong metal–support interfacial interaction. Chemical composition and oxidation state of the hybrid nanostructure were tunable directly in the aerosol state. The results show that the starting temperature of catalysis by Ni-based catalysts reduced by ∼150 °C through the hybridization with CeO2 followed by a direct H2 reduction in the aerosol state. In comparison to Ni-only nanoparticle, the Ni–CeOx hybrid nanoparticle showed stable and high conversion for CH4 and CO2 with a remarkably turnover frequency at low temperature (0.1 s–1 at 450 °C). The amount of coke formation greatly reduced by 18×, whereas the H2/CO ratio was constant at ∼0.8 by a 1.5× of the increase of CO2/CH4 ratio. The work demonstrated a facile route for controlled synthesis of Ni–CeOx hybrid nanoparticles with a very high catalytic activity and stability of DRM. The findings of this study can shed light on the mechanism of Ni–Ce–O synergistic catalysis, which can be especially useful for methane-based energy applications.