• Journal of Adhesion and Interface
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• v.25 no.3
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• pp.75-81
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• 2024

This study analyzes the acid properties of zeolites synthesized through the use of surfactant-based structure-directing agents. To achieve this, zeolites possessing both micropores and mesopores were synthesized using surfactants containing multiple quaternary ammonium molecules. Those surfactants form mesoscale micelles to be mesopores after calcination, while the ammonium moieties direct zeolitic microporous structure. These hierarchical zeolites were then subjected to adsorption of different probe molecules, pyridine, and 2,6-di-tert-butylpyridine, followed by thermal desorption and analysis using FT-IR spectroscopy. The results reveal that unlike conventional zeolites consisting solely of micropores, the hierarchical zeolites exhibit strong acidity not only within the micropores but also on the external surface of the mesopores. This observation suggests the formation of strong acid sites attributed to the hierarchical porous structure induced by surfactant-type structure-directing agents. Consequently, these findings imply potential applications in various catalytic chemical reactions leveraging the surface acidity of zeolites.

• Clean Technology
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• v.15 no.1
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• pp.47-53
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• 2009

Mesoporous aluminas (A-C, A-A, and A-N) were prepared by a templating method using cationic(C), anionic(A), and non-ionic(N) surfactant as a structure-directing agent, respectively. Nickel catalysts supported on mesoporous alumina (Ni/A-C, Ni/A-A, and Ni/A-N) were then prepared by an impregnation method, and were applied to hydrogen production by steam reforming of liquefied natural gas (LNG). Regardless of surfactant type, nickel species were finely dispersed on the surface of mesoporous alumina in the calcined catalysts. It was revealed that interaction between nickel species and support in the reduced catalysts was strongly dependent on the identity of surfactant. LNG conversion and $H_2$ composition in dry gas increased in the order of Ni/A-C < Ni/A-A < Ni/A-N. It was found that catalytic performance increased with increasing nickel surface area in the reduced catalyst. Among the catalyst tested, Ni/A-N catalyst with the highest nickel surface area showed the best catalytic performance.