CO2 methanation over nickel-ZrO2 catalyst supported on carbon nanotubes: A comparison between two impregnation strategies

• Published in: Applied catalysis. B, Environmental Vol. 237; pp. 817 - 825
• Main Authors: Romero-Sáez, M., Dongil, A.B., Benito, N., Espinoza-González, R., Escalona, N., Gracia, F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05-12-2018
• Subjects: Carbon nanotubes; CO2 methanation; Impregnation; Nickel catalysts; Zirconia; Zirconia; Carbon nanotubes; Impregnation; Nickel catalysts; CO2 methanation
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2018.06.045

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•CO2 methanation activity of Ni/ZrO2/TiO2 is affected by the impregnation method.•Co-impregnation showed NiO nanoparticles surrounded by ZrO2 in core-shell structures.•Sequential impregnation showed NiO nanoparticles on the surface or next to ZrO2 nanoparticles.•Zr-O-Ni mixed oxide is formed on the Ni – ZrO2 interface.•The access of the reactant to Ni–ZrO2 interface conditions the catalytic behavior.
Ni-ZrO2 catalysts supported on CNT synthesized by sequential and co-impregnation were tested in the CO2 methanation reaction. The catalysts were characterized using different physico-chemical techniques including BET surface area analysis, TGA, H2-TPR analysis, CO2-TPD analysis, XRD analysis, TEM-EDS analysis and XPS. Both samples were found to be active in the CO2 methanation; however, the catalyst prepared by co-impregnation was notably less active and selective to CH4 than the catalyst synthesized by sequential impregnation method. The characterization results gave significant insight on the disposition of active phases in CNT surface. The catalyst prepared by co-impregnation showed NiO nanoparticles surrounded by ZrO2 in core-shell structures that growth over the CNT, reducing reactant access to Ni and Ni – ZrO2 interface. Additionally, TEM analysis of this catalyst prepared by sequential impregnation showed NiO nanoparticles available and deposited either on the surface or next to the ZrO2 nanoparticles, increasing the extent of the Ni – ZrO2 interface thus improving the catalytic performance.