Dual-production of nickel foam supported carbon nanotubes and hydrogen by methane catalytic decomposition

Uniformly dispersed Ni catalysts supported on SiO₂ wash-coated Ni foams were synthesized by the wet impregnation method and successfully applied for methane catalytic decomposition (MCD) at atmospheric pressure. All the prepared catalysts exhibited high catalytic stability. The effects of reaction temperature, space velocity, Ni loading on the MCD performance and the morphologies of the as-prepared CNTs were investigated. The results show that high reaction temperature, low space velocity, and high Ni loading enhanced the hydrogen concentration in the outlet gases. Additionally, SEM and TEM observations indicate that the size (diameter) distribution of the as-prepared CNTs became broader with increasing reaction temperature and Ni loading, respectively. The uniform nickel-foam-supported CNTs and relatively high concentration of hydrogen were obtained simultaneously at 650 °C and at a weight hourly space velocity of 1 L g⁻¹_cat h⁻¹ by the catalyst with 20 wt% Ni. Raman spectroscopy reveals that the uniform MCNTs had a high degree of amorphization.