1 Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark2 Department of Chemistry, Technical University of Denmark3 Department of Chemical and Biochemical Engineering, Technical University of Denmark4 Haldor Topsoe AS5 Haldor Topsoe AS
Nanocrystals within mesoporous zeolite single crystals
A major factor governing the performance of catalytically active particles supported on a zeolite carrier is the degree of dispersion. It is shown that the introduction of noncrystallographic mesopores into zeolite single crystals (silicalite-1, ZSM-5) may increase the degree of particle dispersion. As representative examples, a metal (Pt), an alloy (PtSn), and a metal carbide (beta-Mo2C) were supported on conventional and mesoporous zeolite carriers, respectively, and the degree of particle dispersion was compared by TEM imaging. On conventional zeolites, the supported material aggregated on the outer surface of the zeolite particles, particularly after thermal treatment. When using mesoporous zeolites, the particles were evenly distributed throughout the mesopore system of the zeolitic support, even after calcination, leading to nanocrystals within mesoporous zeolite single crystals.
Journal of the American Chemical Society, 2005, Vol 127, Issue 22, p. 8098-8102