Functional nanocomposite aerogel (Ni/Al2O3 and Co/Al2O3) catalysts have been developed for the methane decomposition to simultaneously produce COx-free H2 and carbon nanotubes (CNTs). The objectives of this study were to characterize the properties of supported metal aerogel catalysts and the structural morphology of CNTs to elucidate the “base growth” mechanism of CNTs over the unique catalyst systems. Here, Ni/Al2O3 and Co/Al2O3 aerogel catalysts with various metal loadings were synthesized and tested for methane decomposition reaction. Experimental results showed that both Ni/Al2O3 and Co/Al2O3 aerogel catalysts exhibited higher activity and stability than mono and bimetallic Ni, Fe, and Co catalysts synthesized by conventional incipient wetness technique. The properties of fresh and spent aerogel catalysts were characterized by a number of analytical instrumentations including XRD, TGA, Raman, XPS, BET, SEM, and TEM. Structural morphology and growth mechanism of CNT's were investigated and discussed in this presentation. TGA analysis confirmed the absence of amorphous carbon formation during the CH4 decomposition over Ni/Al2O3 and Co/Al2O3 aerogel catalysts. Preliminary experimental results indicated that the CNTs formed over Ni/Al2O3 and Co/Al2O3 aerogel catalysts are all base-growth by nature. The selective synthesis of base-growth CNTs is due to the metal-support interaction and unique porosity presented in aerogel catalysts. Base-growth CNTs possess advantages than conventional tip growth. This is largely because of the ease of separation and regeneration if CNTs are base growth. Regeneration of the spent Ni/Al2O3 aerogel catalyst was conducted by passing carrier gas to the reactor. The regeneration protocol developed can resume initial activity. In this study, a 60 wt% Ni/Al2O3 aerogel catalyst was tested and regenerated repeatedly.

Methane decomposition for the production of COx-free hydrogen and carbon nanotubes over transition metal aerogel catalysts

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.