Mesoporous assembly of 2D manganate nanosheets intercalated with cobalt ions

Mesoporous compound of cobalt-layered manganese oxide was synthesized by self-assembly reaction between 2D manganate nanosheets and cobalt ions. It was found that 2D manganate nanosheets are interstratified with cobalt ions, leading to the formation of porous intercalation heterostructure with expanded surface area of ∼ 44-100 m²/g. The mesopores with the average diameters of ∼ 11-17 nm originate from the house-of-cards type stacking of the layered manganate crystallites. Co K- and Mn K-edge X-ray absorption spectroscopy revealed that both the cobalt and manganese ions are stabilized in octahedral symmetry with the mixed oxidation states of Mn³⁺/Mn⁴⁺ and Co²⁺/Co³⁺. Considering high oxidation states of component metal ions, this porous material is expected to be very useful as redox catalysts and/or lithium intercalation electrodes.