Effect of Mesoporous Silica Buffer Layer on the Orientation of MFI Zeolite Membranes

Growth of MFI zeolite membranes on porous α‐alumina substrates with and without precoated mesoporous silica buffer layer has been performed by in situ crystallization. A preferentially b ‐oriented MFI membrane can be prepared on a mesoporous silica‐coated substrate. A membrane with a randomly oriented and eventually [ h 0 h ]‐oriented top layer is obtained on an uncoated α‐alumina substrate. The chemical properties of the substrate are suggested to have significant effects on the membrane orientation.