Abstract: Molybdovanadophosphoric acid with Keggin structure and its salts are effective catalysts for oxidation reactions. Based on the NMR measurements of ³¹P, ⁵¹V,¹³⁹La, ¹⁷O and ¹H in these catalyst samples in combination with the correspondingIR and DTG determination, it is shown that the addition of lanthanum does not affect the formation of heteropolyacid with Keggin structure. However, lanthanum can exert strong action on water molecules, leading to the existence of more water molecules among the polyanions, which might probably affect catalytically oxidative activity.

Key words: Molybdovanadophosphoric Acid, Salts with Lanthanum NMR, Catalytically Oxidative Activity