Abstract
We evaluated dry reforming of methane in a tubular fixed-bed reactor at various reaction temperatures from 923 to 973 K using different reactant compositions over 10 % Ni/Al
2
O
3
catalyst prepared by a wet impregnation method. Both NiO and NiAl
2
O
4
phases were formed on the catalyst surface during calcination, and the 10 % Ni/Al
2
O
3
catalyst possessed high surface area of 106.36 m
2
g
−1
with fine metal dispersion. The low activation energy observed for formation of NiAl
2
O
4
phase during calcination indicated strong interaction between the NiO form and the γ-Al
2
O
3
support. The NiO phase was completely reduced to metallic Ni
0
form via H
2
reduction. The conversions of CO
2
and CH
4
increased noticeably with increasing CO
2
partial pressure, and the H
2
/CO ratio was always below unity, regardless of reaction conditions. The yield of H
2
was enhanced with growing CO
2
partial pressure, approaching a highest value of about 70 %. The heterogeneous nature of the deposited carbon was evident from the coexistence of carbon nanofibers and graphitic carbon. In addition, the amount of filamentous carbon appeared to be slightly less than that of graphitic carbon. However, these deposited carbons were completely removed by O
2
at below 900 K during temperature-programmed oxidation.