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

Ni-Ce/gamma-Al2O3 catalyst (Ni-Ce-LDH-P) derived from LDHs was synthesized on gamma-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 degrees 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 gamma-Al2O3). It is the chemical bonds that improved the dispersion of Ni crystal and the interaction between Ni and gamma-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. (C) 2017 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.