From the decomposition of methane, hydrogen without carbon oxides can be produced with a
high energy-efficiency, which is attractive for its suitability of utilization in the fuel cells. At a
same time nanocarbon materials with attractive texture and structure can be produced in a large
amount. Toward a simultaneous bulk production of hydrogen and nanocarbon, catalysts based
on nanometer-scale nickel particles prepared from a hydrotalcite-like anionic clay precursor have
been designed and tested to fit the process goals. For hydrogen production, as the equilibrium
methane conversion of the reaction increases with the increase of the reaction temperature, the
process is commercially more attractive if it can be operated at a temperature higher than 1073
K. However, a nickel catalyst has a maximum activity for nanocarbon production at 923 K.
Modification of the catalyst with doping of copper increased the activation temperature and leads
to a production of nanocarbon with an attractive structure. The feasibility and the challenges
met for the coupling of the two process goals is discussed, and some promising results are
presented in this work.
Preparation of b -SiC nanorods with and without amorphous SiO 2 wrapping layers was achieved by carbothermal reduction of sol-gel derived silica xerogels containing carbon nanoparticles. The b -SiC nanorods with amorphous SiO 2 wrapping layers were obtained by carboreduction at 1650 ± C for 1.5 h, and at the end of 1.5 h the temperature was steeply raised to 1800 ± C and held for 30 min; they are typically up to 20 mm in length. The diameters of the center thinner b -SiC nanorods within the amorphous SiO 2 wrapping layers are in the range 10-30 nm, while the outer diameters of the corresponding amorphous SiO 2 wrapping layers are between 20 and 70 nm. The b -SiC nanorods without amorphous SiO 2 wrapping layers were produced by carbothermal reduction only at 1650 ± C for 2.5 h, and their diameters are in agreement with those of the center thinner b -SiC nanorods wrapped in amorphous SiO 2 layers. Large quantities of SiC rod nuclei and the nanometer-sized nucleus sites on carbon nanoparticles are both favorable to the formation of much thinner b -SiC nanorods. The formation of the outer amorphous SiO 2 wrapping layer is from the combination reaction of decomposed SiO vapor and O 2 .
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