Shape-Selective Adsorption of Substituted Benzaldehyde Isomers by a Molecular Sieving Silica Overlayer Prepared by the Chemical Vapor Deposition Method Using Organic Template on Tin Oxide

摘要

The chemical vapor deposition of a silica overlayer in the presence of template molecules was examined on tin oxide in order to construct surface cavities with a molecular sieving property.On a SiO_2/SnO_2 sample prepared using a benzaldehyde template,4-chlorobenzaldehyde and 4-methylbenzaldehyde were adsorbed,while 2-chlorobenzaldehyde and 2-methylbenzaldehyde were not adsorbed.The adsorption of 3-chlorobenzaldehyde was controlled by the thickness of the layer,i.e.,the depth of the cavity.It was adsorbed by a shallow cavity,but not by a deep cavity.Thus the shape selectivity due to the shapes of the adsorbate molecule and the cavity was obtained.