Improved low-temperature activity of Ni-Ce/γ-Al2O3 catalyst with layer structural precursor prepared by cold plasma for CO2 methanation

Ni-Ce/γ-Al2O3 catalyst (Ni-Ce-LDH-P) derived from LDHs was synthesized on γ-Al2O3. Plasma technology was employed to its preparation process. Impregnation method and thermal calcination and reduction technology were used to prepare reference catalysts (Ni-Ce-LDH-C, Ni-Ce-P and Ni-Ce-C). CO2 methanation was chosen as the probe reaction. XRD, BET, SEM, TEM and CO2-TPD were used to characterize the microstructure and properties of catalyst. Experimental results showed that Ni-Ce-LDH-P catalyst with smaller Ni size, better Ni dispersion and higher alkalinity exhibited outstanding low-temperature activity at range of 200-350 °C. Characterization results showed that the precursor of Ni-Ce-LDH-P catalyst presented in lamellar shape, inferring the formation of chemical bonds among Ni, Ce and Al (from γ-Al2O3). It is the chemical bonds that improved the dispersion of Ni crystal and the interaction between Ni and γ-Al2O3. Meanwhile, the plasma technology with relatively low temperature prevented the sintering and agglomeration of Ni during the preparation process. Therefore, the excellent performance of Ni-Ce-LDH-P catalyst should be ascribed to the synergy of the unique lamellar structure and the special characteristics of “high energy at relatively low temperature” of plasma technology.