Hybrid plasma-catalytic methanation of CO2 at low temperature over ceria zirconia supported Ni catalysts

• Ni/CZ catalysts are only active at high temperature.
• Low methanation process by coupling plasma and Ni/CZ catalyst.
• High selectivity to CH4 with plasma/Ni/CZ catalyst system.
• Stability of the catalyst with time on stream.

A hybrid plasma-catalytic system was used in for the hydrogenation of carbon dioxide (CO2) into methane (methanation) at atmospheric pressure and very low temperature using a dielectric barrier discharge (DBD) plasma reactor packed with Ni-CexZr1−xO2 catalysts. Three catalysts were prepared by a conventional wet impregnation method, using 15 wt% of Ni loading over ceria-zirconia mixed oxides having different Ce/Zr ratios. The physico–chemical features of both catalysts and supports were evaluated by means of X-Ray Diffraction (XRD), Temperature-Programmed Reduction of H2 (H2-TPR), Temperature Programmed-Desorption of CO2 (CO2-TPD) and Transmission Electron Microscopy (TEM). The methanation experiments in the absence or in the presence of plasma were carried out in the temperature range of 90–420 °C. The hybrid plasma 15NiCZ5842 catalyst combination was found to efficiently convert CO2 into methane even at low temperature. Indeed, CO2 conversions as high as 80%, together with 100% selectivity toward methane was measured in the presence of plasma at 90 °C. On the contrary in the absence of plasma, the same conversion and selectivity were only achieved at much higher temperatures around 300 °C, for the same catalyst.

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