Highly efficient Ni-ZrO2 catalyst doped with Yb2O3 for co-methanation of CO and CO2

Authors:   Yan-Hui Huang, Ji-Jie Wang, Zhi-Ming Liu, Guo-Dong Lin, Hong-Bin Zhang

Abstract:
A type of highly efficient Ni-ZrO₂ catalysts doped with Yb₂O₃ for co-methanation of CO and CO₂ was developed, and displayed excellent activity and thermal stability. Over the Ni₆Zr₂Yb₂ catalyst under the reaction conditions of 0.1 MPa and 573K, the observed total conversion of CO and CO₂ (denoted as X(CO and CO₂)) maintained continuously at a high level of ∼97.4% during 25–126 h after the reaction started, with the corresponding STY(CH₄) reaching ∼9.11 g ^h−1 g⁻¹. The results of heat-resisting test showed that, over the Ni₆Zr₂Yb₂ catalyst after undergoing 24 h of the methanation operation at 1073K followed by going down to 573K,the X(CO and CO₂) still maintained stable atthe level of 89%; whereas X(CO and CO₂) observed on the other two reference systems, Ni₆Zr₄ and Ni₆Zr₂Sm₂, which both underwent the similar heat-resisting test at 923K and 1023K, respectively, fell to 2.8% and 2.4%, respectively. The results of the catalyst characterization demonstrated that the high activity, and especially the extremely high thermal stability, of the Ni₆Zr₂Yb₂ catalyst for CO and CO₂ methanation were associated with the formation of (Zr-Yb)Oy oxide with c-ZrO₂ structure. The pronounced promoter action of Yb₂O₃ may be due to the high solubility of Yb₂O₃ in ZrO₂ lattice as the ionic radius of Yb³⁺ (0.087 nm) is quite close to that of ZrIV (0.079 nm). Solution of a considerable amount of Yb³⁺ in the ZrO₂ host resulted in the formation of (Zr-Yb)Oy oxide with simple c-ZrO₂ structure. It is the major factor for the high activity and high thermal stability of the Ni₆Zr₂Yb₂ catalyst.

Keywords:
Ni-ZrO₂ catalyst
Yb₂O₃-doped Ni-ZrO₂ catalyst
CO and CO₂ co-methanation

Published in: Applied catalysis A: General  (Volume 466, Pages 1-314, 10 September 2013)

Publisher: Elsevier  

ISSN Information: 0926-860X

Highly efficient Ni-ZrO2 catalyst doped with Yb2O3 for co-methanation of CO and CO2

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