Synthesis and Characterization of Large Crystal Transition Metal Substituted Zeolite ZSM-5

Transition metal contg. ZSM-5 has shown promise as a heterogenous catalyst. Substitution of the metal has been commonly achieved by ion exchange. An alternative is to incorporate the metal into the oxide framework during synthesis. This work will present the growth of large crystals of transition metal substituted ZSM-5 prepd. by direct addn. of the metals to the synthesis gels. These crystals are ∼25-85 μm on the long axis, which is one to two orders of magnitude larger than previously reported in the literature. Powder X-ray diffraction shows only a single ZSM-5 cryst. phase for gel compns. consisting of up to 0.1% of the T-atoms as transition metals. Washing of the products with methanolic HCl indicates that the metal content of the crystals is not preferentially contained in an external surface layer and is resistant to leaching