Methane decomposition over Pd promoted Ni/MgAl2O4 catalysts for the production of COx free hydrogen and multiwalled carbon nanotubes

Abstract This article reports the synthesis, characterization and catalytic performance of Pd promoted Ni/MgAl 2 O 4 spinel catalysts for the thermal decomposition of methane into hydrogen and carbon nanotubes. The as-synthesized catalysts were characterized for their structural, textural, morphological properties. The catalytic properties of the Ni/MgAl 2 O 4 catalyst were found to be enhanced with Pd promoter. It effectively increased the surface area of the catalyst without affecting the pore parameters and improved the fine dispersion of NiO particles on the surface of the magnesium aluminate. The reduction temperature of Ni/MgAl 2 O 4 was found to be lowered after Pd deposition. Moreover, the Pd promoted catalyst provided high catalytic activity and stability for methane decomposition. A maximum hydrogen yield of ∼57% was obtained over the Pd catalyst at a reaction temperature of 700 °C without any deactivation for 420 min of time on stream. Moreover highly uniform, interwoven and thin multi-walled carbon nanotubes with high graphitization degree were deposited over the catalysts.