Ni/ZrO₂-CeO₂ catalysts for the simultaneous production of hydrogen and carbon nanotubes

The catalytic methane decomposition (CMD) using Ni/ZrO₂-CeO ₂ catalysts for the simultaneous production of hydrogen and carbon nanotubes, was studied on samples prepared by different synthesis methods. The catalysts were synthesized by the impregnation and coprecipitation methods with or without ultrasound treatment. X-ray diffraction (XRD), Raman spectroscopy and high resolution transmission electron microscopy (HRTEM) were the main characterization techniques. It was observed that the Ni impregnated catalyst with ultrasound treatment increases significantly the production of hydrogen and carbon nanotubes in the CDM at 500 °C. The results also indicated that the synthesis of catalysts via coprecipitation generates a higher number of encapsulated Ni particles by both, the ZrO₂-CeO₂ support and the produced carbon at the end of the reaction.