A highly dispersible, magnetically separable and environmentally friendly nano-sized catalyst for water oxidation

•Using hydrogen to store sustainable energies is a promising strategy in the near future.•Mn oxides are highly attractive as catalysts for water oxidation.•We consider Mn oxide/SiO2/cobalt nanoparticles as a water-oxidizing catalyst toward water oxidation.•We report a dispersible, separable and environmentally friendly catalyst.

The reaction of KMnO4 with cobalt nanoparticles coated with SiO2 layers forms a highly dispersible, magnetically separable and environmentally friendly catalyst toward water oxidation. The compound was characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, X-ray Photoelectron Spectroscopy, X-ray diffraction, electron spectroscopy, Fourier transform infrared spectroscopy and atomic absorption spectroscopy. The nano-sized catalyst shows self-healing in the presence of cerium(IV) ammonium nitrate and under the water-oxidation conditions. The turnover frequencies for the catalyst toward water oxidation in the presence of cerium(IV) ammonium nitrate and [Ru(bpy)3]3+ are 0.15 and 0.25 (mmol O2/mol Mn·s), respectively.

Graphical abstractThe reaction of KMnO4 with cobalt nanoparticles coated with SiO2 layers forms a highly dispersible, magnetically separable and environmentally friendly catalyst toward water oxidation.Figure optionsDownload full-size imageDownload as PowerPoint slide