Incorporation of vanadium species in a dealuminated β zeolite

V-loaded β zeolites can be prepared by a two-step post-synthesis method which consists of first creating vacant T-sites by dealumination of the β zeolite with nitric acid, then contacting them with an ammonium metavanadate solution; the SiOH consumption and the nature of the incorporated V species are characterized by IR, UV-VIS and <SUP>29</SUP>Si MAS NMR spectroscopies