Study on physico-chemical properties of tin dioxide based gas sensitive materials used in condensation reactions of n-butanol

摘要

The physico-chemical properties of primary alcohol conversion catalysts SnO_2,CeO_2 and tin dioxide modified with rhodium,cerium or both,are presented.The synthesis of pure SnO_2 was performed with the Okazaky method.Admixturing with rhodium was made by the impregnation method.Addition of cerium was achieved by co-precipitation.The obtained materials based on tin dioxide were monophase materials of tetragonal structure,characteristic for SnO_2.As a result of introducing cerium as a dopant of tin oxide(IV),the character of active centers was changed.The obtained monophase materials of compositions Sn_(0.93)Ce_(0.07)O and Sn_(0.925)Ce_(0.07)Rh_(0.005)O_2 revealed a large number of strong Lewis acidic centers on the surface.As a result of the addition of CeO_2 to basic tin dioxide there was a clear modification of catalytic properties appearing in these materials.The authors try to explain a mechanism of condensation of alcohol,aldehyde or acid to ketone on their surface with the participation of Lewis acidic centers.