Hydrothermal synthesis and characterization of double phase magnesium vanadium oxides

Abstract

Vanadium is a transition element (atomic weight 50.94) with valences -1, 2, 3, 4, and 5. Vanadium acts a big part in human. Minimal amounts of vanadium cause several kinds of effects in body such as binding transferrin, ferritin and iron binding proteins [1]. On the other hand, the electronic conductivity of derivatives of MgxVyOz type compounds is magnitude higher than that of the vanadium oxide without magnesium. Also, magnesium containing compounds exhibit significantly improved kinetic behaviour and rate capability [2-3]. Magnesium-vanadium oxides are the top catalyst for the oxidative dehydrogenation of alkanes [4]. V2O5, a member of acidic oxide family, can react rapidly with the basic MgO resulting magnesium vanadates. Various magnesium vanadates such as magnesium orthovanadate, magnesium pyrovanadate and magnesium metavanadate can be formed in different compositions of vanadium pentaoxide and magnesium oxide [5]. In the past years, magnesium vanadates were synthesized by high temperature calcination method [5], impregnation pathway [6-8], citrate methods [9], absorption of vanadyl compounds [10-11], coprecipitation [6,9,12-15]. Catalytic activity of vanadium containing magnesium oxides is higher than magnesium oxide without vanadium [4]. Solid state methods produce low surface area. So, high temperature calcination methods were avoided to get high surface area [4]. In this perspective, we aim to synthesis of magnesium vanadium oxide, having staggering unusual properties, under mild hydrothermal conditions.