Synergetic effect of Ni-CeO2 bimetallic catalyst for an effective decomposition of methane to hydrogen and filamentous nanocarbons

The work attempts to synthesis nickel-ceria bimetallic catalysts supported on porous carbon template, thermally stable at 850 °C, for dehydrogenation of methane to hydrogen and carbon nanostructures. A series of bimetallic Ni catalysts were synthesized by varying the % ceria content (30Ni-5CeO2/AC, 30Ni-10Ce O2/AC, and 30Ni-15CeO2/AC) using the incipient wetness impregnation approach. Among the set of bimetallic catalysts, the 30Ni-5CeO2/AC catalyst was found to offer highest methane conversion and stability. A maximum conversion of 90% was achieved with 40% methane feed concentration along with good catalyst stability. The promoter ceria at low concentration enhanced the dispersion of metal over the catalytic surface, resulting in adequate metal-support interaction. The ability of the carbon support along with promoter ceria enhanced the thermal stability of the Ni catalyst up to 850 °C, offering high conversion and catalyst stability has been the highlight of the work. Advanced analytical techniques were used to characterize the catalyst's structural, textural, and morphological properties both before and after the reaction. The morphological study of the best-performing catalyst demonstrated the formation of dense carbon nanotubes through tip-growth mechanism exhibiting a high aspect ratio.