Abstract: SAPO-34 molecular sieves have been successfully synthesized onto the cordierite substrates by hydrothermal technique, and characterized by XRDand SEMmethods.The results show that SAPO-34 layers with the thickness about₃₀μm are evenly distributed onto the inner walls of the cordierite substrate, which results in a weight increase of15%_25% of the substrate.The molar ratio of Et₃N/Al₂O₃had an important effect on the nature of the molecular sieve product crystallized on the substrate.When n SAPO-34 was crystallized on the cordierite substrate; whereas when n (Et₃N)/n (Al₂O₃)=2.5 , a mixture product of SAPO-34 and SAPO₅was formed on the substrate.In order to explore the mechanism of SAPO-34 formation on the cordierite substrate, the changes of the crystallization process on the substrate as well as in the solution has also been investigated

Key words: Cordierite, In situ synthesis, Monolithic catalysts, Zeolite layer, SAPO-34, SAPO-5