SYNTHESIS CHARACTERIZATION AND APPLICATIONS OF NANOSIZE METAL OXIDES

Abstract

newline The metal oxides represent little but an important and diversified part of the entire inorganic compounds. These metal oxides are widely used in paint or plastic industry and also as fillers or pigments in pulp and paper industry [1-3]. Their applications in ceramic [4] and electronic technology [5] are widespread and play an important role for the environmental purification [6-12], sensing of toxic gases [13-18] and organic/inorganic transformations [19-23]. Metal oxides are known to be the weather and light fast, chemically inert, and most heat-resistant pigments. They are the result of high temperature combinations and consist exclusively of metal cations and oxygen anions. Although metallic components of metal oxides may belong to each group of the periodic table, they can be ranked into five main categories according to their chemical structure and reactivity: silicates, aluminates, titanates, chromites and ferrites. The pure metal oxide/mixed metal oxides can be utilized as catalyst for many applications [24-32]. In particular, there is a paucity of information on the specific sites responsible for the catalytic activity of bulk surfaces. The active catalytic components of metals or metal oxides mainly decide the nature of a catalytic reaction with respect to selectivity of the reaction products and their rates of formation. A promoter is a component of the catalyst which is capable of modifying its properties e.g. acidity of the major component of the catalyst to make it more desirable. The nature, oxidation state and the pore size of the active catalyst dictate major direction of a catalytic reaction [