Performance of Ni/MgAl2O4 Catalyst Obtained by a Metal-Chitosan Complex Method in Methane Decomposition Reaction with Production of Carbon Nanotubes
This paper describes the synthesis of Ni/MgAl2O4 catalysts using a method developed by our group with the objective of obtaining a material with more homogeneous composition, more porous structure and greater surface area compared with other spinel preparation methods. The performance of the material obtained was evaluated in the catalytic decomposition of methane, which is a potential alternative route for obtaining pure hydrogen and valuable carbonaceous materials. The textural properties of the catalyst were investigated by X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET and BJH methods), and temperature-programmed reduction (TPR) analysis. The nature of the carbon deposits was investigated by thermogravimetric analysis (TGA), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The influence of the operating conditions on the characteristics of the carbon deposited was studied. The results demonstrated the efficiency of the catalyst in this reaction with the formation of CNTs, irrespective of the operating conditions employed. In general, multiple-walled nanotubes (MWCNTs) were preferentially obtained, and when a diluted flow of CH4 was used the CNTs presented a greater degree of graphitization.
KeywordsMagnesium aluminate spinel Metal-chitosan complex Methane decomposition Carbon nanotubes
The authors are grateful to Universidade Federal de Santa Catarina (UFSC) for access to facilities including LCME, LDRX and LabMat, and to the Brazilian government agency Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support.
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