CO methanation over ZrO2/Al2O3 supported Ni catalysts: A comprehensive study

• The highly active and thermally stable methanation catalyst was obtained, which shows superior resistance to carbon forming and Ni sintering.
• A promotion of the stability, anti-carbon deposition and anti-sintering performance of Ni/Al2O3 catalyst modified by ZrO2 are obtained by a comparative analysis of fresh and spent catalyst.
• The competing deactivation role of carbon deposition and sintering at different reaction temperatures are reported in the CO methanation over Ni/ZrO2-Al2O3 catalyst.

A series of ZrO2/Al2O3 composite oxides with different ZrO2 contents were prepared by impregnation method. The NiO/ZrO2/Al2O3 catalysts for CO methanation were prepared and tested in a tubular microreactor under the condition of T = 300–650 °C, P = 1.5 MPa, GHSV (gas hourly space velocity) = 10,000 h− 1, and H2/CO = 3. The results revealed that adding ZrO2 restrains the formation of NiAl2O4, weakens the Ni–Al2O3 interaction, and makes the catalyst more easily reduced, enhancing significantly the activity of catalyst. Especially, among these catalysts, 20Ni/40ZA catalyst with ZrO2 content of 40 wt.% exhibits high CO conversion and CH4 selectivity in a broad temperature region of 300–550 °C. Moreover, 20Ni/40ZA performs superior stability than 20Ni/Al2O3. The added ZrO2 also improves the anti-carbon deposition and anti-sintering performance of Ni/Al2O3 catalyst.

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