Ni-Fe layered double hydroxide derived catalysts for non-plasma and DBD plasma-assisted CO2 methanation

A series of bi-metallic layered double hydroxide derived materials, containing a fixed amount of Ni promoted with various amounts of Fe were obtained by co-precipitation. The synthesized materials were characterized by X-ray diffraction (XRD), temperature-programmed reduction (H-2-TPR), temperature-programmed desorption of CO2 (CO2-TPD), elemental analysis and low temperature N-2 sorption and tested as catalysts in CO2 methanation at atmospheric pressure. The obtained results confirmed the formation of mixed nano-oxides after thermal decomposition of the precursor and suggest successful introduction of both nickel and iron into the layers of Layered Double Hydroxides (LDHs). The introduction of Fe into the layered double hydroxides changed the interaction between Ni and supports matrix as proven by temperature programmed reduction (H-2-TPR). The introduction of low amount of iron influenced positively the catalytic activity in CO2 methanation at 250 degrees C, with CO2 conversion increasing from 21% to 72% with CH4 selectivity ranging from 97 to 99% at 250 degrees C. No other products, except CH4 and CO were registered during the experiments. In order to enhance the catalytic activity a non-thermal plasma created by dielectric barrier discharge was applied. The obtained results prove that plasma could replace the need of heating the reactor in a dynamic system working temporarily when excess energy is available. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.