Manganese oxides as water-oxidizing catalysts for artificial photosynthetic systems: The effect of support

• Using hydrogen to store sustainable energies is a promising strategy in near future.
• Mn oxides are highly attractive as catalysts for water oxidation.
• We consider Mn oxide on CuO, NiO, MgO, SiO2 or ZrO2 as catalysts toward water oxidation.
• A turnover frequency ∼5 based on Mn was observed for Mn oxides on NiO.

Herein the effect of support on water-oxidizing activity of amorphous Mn oxides was investigated. We used nanoparticles of CuO, NiO, MgO, SiO2 or ZrO2 as support and placed Mn oxides on these oxides. The compounds were synthesized by a simple procedure and characterized by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray diffraction spectrometry. In the next step, the water-oxidizing activities of these compounds were considered in the presence of cerium(IV) ammonium nitrate. We found that the efficiency of Mn oxide toward water oxidation depends upon the nature of the support. A turnover frequency ∼5 based on Mn was observed for Mn oxides on NiO.

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