Ta(V)-Single Site BEA Zeolite by Two-Step Postsynthesis Method: Preparation and Characterization

摘要

Ta_(1.0)SiBEA and Ta_(2.0)SiBEA zeolites are prepared by a two-step postsynthesis method involving first the creation of vacant T-atom sites associated with silanol groups by dealumination of TEABEA zeolite with nitric acid and then the impregnation of the resulting SiBEA zeolite with tantalum ethoxide (Ta(OC2H5)5 precursor. This postsynthesis procedure allows to incorporate Ta into the BEA framework as isolated mononuclear Ta(V) ions and to obtain Ta(V)-single site BEA zeolite as evidenced by XRD, ~(29)Si MAS NMR, ~1H-~(29)Si CP MAS NMR, IR, ~1H MAS NMR, DR UV-Vis.