H-1 AND V-51 HIGH-RESOLUTION SOLID-STATE NUCLEAR-MAGNETIC-RESONANCE STUDIES OF SUPPORTED V2O5 TIO2 CATALYSTS/

H-1 solid state NMR data show the existence of several types of hydrox yl groups on TiO2 surface, depending on the surface impurities. VOCl3 selectively interacts with these groups. According to V-51 NMR data, t he structure of the surface vanadium complexes, independently of the p reparation method, is determined by the type of surface hydroxyls. On clean TiO2 surface at low vanadium concentration two types of surface complexes with vanadium in the distorted tetrahedral environment of ox ygen atoms are formed, one of them containing OH groups in the coordin ation sphere. At high V content associated species, with V in octahedr al coordination, are formed.