Catalytic performance of MnOx–NiO composite oxide in lean methane combustion at low temperature

Authors:   Yagang Zhang, Zhangfeng Qin, Guofu Wang, Huaqing Zhu, Mei Dong, Shuna Li, Zhiwei Wu, Zhikai Li, Zhonghua Wu, Jing Zhang, Tiandou Hu, Weibin Fan, Jianguo Wang

Abstract:
A series of MnO_x–NiO composite oxide catalysts were prepared by co-precipitation method and used in the catalytic combustion of lean methane at low temperature. Compared with the corresponding single NiO and MnO_x oxides, the MnO_x–NiO composite oxide with proper composition exhibits much higher catalytic performance in the lean methane oxidation. XRD and HRTEM results demonstrate that MnO_x–NiO is in the form of a Ni–Mn–O solid solution. XAFS and XPS results indicate that the content of manganese in MnO_x–NiO has a significant influence on the oxidation state of manganese and the crystal defect of nickel oxide. MnO_x–NiO catalyst with an atomic Mn/(Mn ⁺ Ni) ratio of 0.13 is provided with abundant highly dispersed manganese species of higher valence (Mn⁴⁺) and higher coordination number as well as certain nickel vacancies, due to the strong interaction between Ni and Mn species. H₂-TPR and O₂-TPD results show that the MnO_x–NiO composite oxide exhibits better reducibility and oxygen mobility than NiO. All these characterizations suggest a prominent synergism between NiO and MnO_x in the MnO_x–NiO composite oxide, which contributes to its high performance in the lean methane combustion.

Keywords:
Nickel oxide
Manganese oxide
MnO_x–NiO composite oxide
Lean methane
Catalytic combustion

Published in: Applied catalysis B: Environmental  (Volume 129, Pages 1-614, 17 January 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Catalytic performance of MnOx–NiO composite oxide in lean methane combustion at low temperature

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