Multistep synthesis of metal sulfide clusters: A novel zeolite modification method

A general approach has been proposed for incorporating high concentrations of modifier metals into high-silica zeolites. MFI zeolites have been modified with mono- and polymetallic sulfide clusters of copper, manganese, zinc, cobalt, and nickel. The metal incorporation sequence and the nature of the anion have been shown to influence both the total content and the ratio of the modifiers in the zeolite. Using multistep syntheses, we have prepared zeolites containing superstoichiometric amounts of modifier metals. Using a variety of physicochemical characterization techniques, the zinc-containing sample has been shown to have a uniform modifier distribution. The Cu-MFI-50 and Mn-MFI-50 zeolites have been characterized by electron paramagnetic resonance and shown to contain isolated Cu 2+ and Mn 2+ ions stabilized on the aluminum lattice site.