Vanadium compounds, catalysts with hydrogen peroxide

Apart from raising the pH level, precipitation can be induced in a variety of other ways. Anionic species, for example, can be deposited on the surface of suspended carriers by decreasing the pH level. This procedure has been used for vanadium(V) and Mo(Vl). Oxidation at a pH level where the ions of the lower valency are soluble and the oxidized species insoluble, can also be utilized to precipitate from a homogeneous solution. Iron(lI/lll) and Mn(IlI/rV) are cases in point. Oxidation can be effected by dissolved agents like nitrate, or electro-chemically. Reduction to insoluble ionic compounds has been applied with Cr, Cu, and Mo. Reduction to the metal has also been practised, and appears to work especially well with noble metals. Decomplexing is another possibility e.g. destruction of complexing EDTA by hydrogen peroxide has been employed to produce supported catalysts. 

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