This technology features a multi-layered nanosheet structure comprising sandwich-type hybrid 2D nanosheets, where mesoporous carbon layers are anchored to both sides of exfoliated metal oxide nanosheets such as MnO2, TiO2, and RuO2. The anchoring of the carbon layers reduces a portion of the metal cations within the metal oxide, thereby enhancing electron transfer and catalytic activity.
Previously, mesoporous carbon or metal oxides were used individually as catalysts, which resulted in low electrocatalytic activity and limited electron transfer rates. Furthermore, these materials suffered from poor durability due to structural instability during repeated electrochemical reactions.
This technology involves first anchoring mesoporous silica layers on both sides of the nanosheets, coating them with a carbon precursor such as phenol-formaldehyde or lignin, and carbonizing them in a reducing atmosphere. The silica is then etched away with an alkaline solution, leaving behind mesoporous carbon layers 5–30 nm thick. Strong interfacial electronic coupling between the carbon and the oxide creates active sites such as Mn3+, while the nanosheets stack like a house of cards to provide a large surface area and pore volume. Applicable to metal-air battery cathodes, fuel cell oxygen reduction reaction (ORR) catalysts, and supercapacitor electrodes, this technology enables the use of low-cost manganese-based ORR catalysts as a substitute for platinum, while ensuring long-term operational durability.
This invention was developed with support from the Center for Hybrid Interface Materials at the Ministry of Science and ICT.
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