|
|
Effect of surface structure on the catalytic behavior of Ni:Cu/Al and Ni:Cu:K/Al catalysts for methane decomposition
S. Tajammul Hussain*;Sheraz Gul;Muhammed Mazhar;Dalaver H. Anjum;Faical Larachi
2008, 17(4):
374-382.
DOI:
Methane decomposition using nickel, copper, and aluminum (Ni:Cu/Al) and nickel, copper, potassium, and aluminum
(Ni:Cu:K/Al) modified nano catalysts has been investigated for carbon fibers, hydrogen and hydrocarbon production.
X-ray photoelectron spectroscopy (XPS), static secondary ion mass spectrometry (SSIMS), thermal gravimetric analysis (TGA),
Fourier transform infrared (FT-IR), secondary electron microscopy/X-ray energy dispersive (SEM-EDX), and temperature programmed
desorption (TPD) were used to depict the chemistry of the catalytic results. These techniques revealed the changes in
surface morphology and structure of Ni, Cu, Al, and K, and formation of bimetallic and trimetallic surface cationic sites with
different cationic species, which resulted in the production of graphitic form of pure carbon on Ni:Cu/Al catalyst. The addition
of K has a marked effect on the product selectivity and reactivity of the catalyst system. K addition restricts the formation of
carbon on the surface and increases the production of hydrogen and C2, C3 hydrocarbons during the catalytic reaction whereas
no hydrocarbons are produced on the sample without K. This study completely maps the modified surface structure and its relationship
with the catalytic behavior of both systems. The process provides a flexible route for the production of carbon fibers
and hydrogen on Ni:Cu/Al catalyst and hydrogen along with hydrocarbons on Ni:Cu:K/Al catalyst. The produced carbon fibers
are imaged using a transmission electron microscope (TEM) for diameter size and wall structure determination. Hydrogen
produced is COx free, which can be used directly in the fuel cell system. The effect of the addition of Cu and its transformation
and interaction with Ni and K is responsible for the production of CO/CO2 free hydrogen, thus producing an environmental
friendly clean energy.
|
