CO x -free hydrogen and carbon nanofibers production by methane decomposition over nickel-alumina catalysts

Methane dissociation to COx-free hydrogen and carbon nanofiber over Ni-Cu/Al2O3 catalysts

“…As can be observed the crystallite size decreased with grow thin copper content, which can be due to the role of copper in improvement of the particle dispersion. It is notable that higher Cu content created smaller crystallite size while increasing in Ni content leads to the bigger crystallites size [22].…”

“…In the present work the sol-gel method was employed for preparation of alumina. In this method aluminum tri-isopropylate (98% purity, Merck) was initially hydrolyzed in distillated water by stirring at 80-85 ºC for 1 h. Afterwards, for sol creation, nitric acid (65% purity, Merck) with a HNO 3 /Al molar ratio of 1:1 was added to the prepared solution the produced sol was aged at 98 ºC for 12 h. Then, the sol was maintained at 98 ºC for 2 h in air and dried at 80ºC and calcined at 450 ºC for 4 h [22,23]. The nickel based catalysts were prepared via wet impregnation method.…”

“…CH 4 conversion (%) as function of Cu content and reaction temperature (Reaction conditions: CH 4 :N 2 =3:7, GHSV=24,000 ml.h -1 g cat -1 ) (50%Ni/Al 2 O 3[22]). …”

Thermocatalytic decomposition of methane to COx-free hydrogen and carbon over Ni–Fe–Cu/Al2O3 catalysts

“…SEM images of (a): prepared alumina with sol-gel method as catalyst support[9], (b): 50%Ni/Al 2 O 3[9], (c): 50%Ni-10% Fe/Al 2 O 3[10] and (d): 50%Ni-10%Fe-10%Cu/Al 2 O 3 (prepared catalysts calcined at 450 C).…”

Methane Pyrolysis for CO2‐Free H2 Production: A Green Process to Overcome Renewable Energies Unsteadiness

“…Transition metals like Ni, Fe, and Co have been widely studied as active species for methane pyrolysis [20,29,[57][58][59][60][61] due to their high activity, moderate operating temperature, and the possibility of producing valuable carbon nanotubes as by-product [62]. Their 3d orbitals are partially filled and can accept electrons from the C-H bonds of methane, which facilitates its decomposition [20,29,[57][58][59][60][61]63]. These metals also offer high solubility and carbon diffusion through their crystalline structure [64].…”