Water oxidation by simple manganese salts in the presence of cerium(IV) ammonium nitrate: towards a complete picture

For the first time, using scanning electron microscopy, transmission electron microscopy, X-ray absorption near edge structure and extended X-ray absorption fine structure X-ray diffraction, it is showed that MnCO3, MnWO4, Mn-3(PO4)(2) center dot 3H(2)O, MnS and Mn(VO3)(2)center dot xH(2)O under the water-oxidation conditions and in the presence of cerium(IV) ammonium nitrate, are converted to Mn oxide without a high-range order. A mechanism is proposed for such conversion and as Mn oxide is an efficient water-oxidizing catalyst, it is thus a candidate as a contributor to the observed catalytic activity.