Reversible Redox Property of Co(III) in Amorphous Co-doped SiO/γ-AlO Layered Composites.

This paper reports on a unique reversible reducing and oxidizing (redox) property of Co(III) in Co-doped amorphous SiO/γ-AlO composites. The Fenton reaction during the HO-catalyzed sol-gel synthesis utilized in this study lead to the partial formation of Co(III) in addition to Co(II) within the composites. High-resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analyses for the composite powder sample with a composition of Al:Si:Co = 85:10:5 showed the amorphous state of the Co-doped SiO that modified γ-AlO nanocrystalline surfaces.