Influence of Metal Composition and Support Material on Carbon Yield and Quality in the Direct Decomposition of Methane.

A series of catalysts were synthesized via a combination of evaporation-induced self-assembly and spray pyrolysis; they were then applied to the direct decomposition of methane. Among them, Ni-Cu/MgO catalysts exhibited the smallest Ni particle size (~9 nm), attributed to the Cu-induced suppression of Ni crystal growth during synthesis. These catalysts achieved the highest carbon yield, primarily due to the enhanced dispersion and nanoscale size of Ni particles. The interaction between methane and the catalysts, as well as the structural and electrical properties of the resulting carbon nanotubes, such as crystallinity and conductivity, were investigated with respect to the support material (MgO vs. AlO) and metal composition (Ni vs. Ni-Cu). The findings provide valuable insights for designing advanced catalyst systems for the efficient conversion of methane into high-value carbon-based materials.