Synthesis of Ni-CeO2 catalyst for the partial oxidation of methane using RF thermal plasma

Ni-CeO2 catalysts with a nickel content of 50 mol% were prepared using RF thermal plasma, and their catalytic activities for methane partial oxidation were characterized. For the synthesis of Ni-CeO2 catalysts, a precursor containing Ni (similar to 5-mu m diameter) and CeO2 (similar to 200-nm diameter) powders were heated simultaneously using an RF plasma at a power level of similar to 52 kVA and a powder feeding rate of similar to 120 g/h. From the X-ray diffraction data and transmission electron microscopy images, the precursor formed into high crystalline CeO2 supports with nanosized Ni particles (< 50-nm diameter) on their surfaces. The catalytic performance was evaluated under atmospheric pressure at > 500 degrees C and a CH4:O-2 molar ratio of 2:1 with Ar diluent. Although the Ni content was high (similar to 50 mol%), the experimental results reveal a methane conversion rate of > 70%, selectivities of CO and H-2 greater than 90% and slight carbon coking during an on-stream test at 550 degrees C for 24 h. However, at 750 degrees C, the on-stream test revealed the formation of filament-like carbons with an increased methane conversion rate over 90%. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.