Stable NiO-CeO2 nanoparticles with improved carbon resistance for methane dry reforming

High surface area mixed oxide 8.7% NiO-CeO2 nanoparticles (122 m(2)/g; 6-7 nm) were prepared using a reversed microemulsion method, and were tested for dry methane reforming (DRM). The catalytic activity of these nanoparticles remains stable under the severe conditions of DRM (700 degrees C), and they show better carbon resistance than conventional NiO-CeO2 catalysts prepared without control of the size. The activity and selectivity of nanoparticles and reference catalyst are similar, but nanoparticles reduce the accumulation of carbon by 63% during the DRM tests, which is a key feature for this reaction. XPS and H-2-TPR suggest that the improved carbon resistance of the nanoparticles is due to the better interaction and cooperation between NiO and CeO2 mixed phases. In nanoparticles, the participation of cerium cations in the redox processes taking place during DRM stabilizes cationic species of nickel. On the contrary, the catalyst prepared without control of the size suffers segregation of Ni during DRM reaction, and segregated Ni explains the higher catalytic formation of carbon. (C) 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.