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[摘要]：Graphene oxide, with sufficient oxygen-containing groups, is integrated with electronically conductive carbon nanotubes to be explored as an efficient metal-free catalyst for the oxygen reduction reaction. Preliminary theoretical calculations with the density functional theory method indicate that the existence of graphene oxide is favorable for the adsorption and subsequent four-electron reduction reactions of O-2. Furthermore, this oxygen-enriched hybrid material was tested as a cathode in aprotic/aqueous hybrid electrolyte Li-air batteries. The hybrid material exhibited a very low overpotential (the voltage gap at 0.1 mA cm(-2) is only 0.17 V) and better electrocatalytic performance owing to abundant oxygen containing groups and its excellent electroconductivity. These experimental and theoretical demonstrations should provide an important mechanistic insight into carbon-based metal-free catalysts in fuel cells and metal-air battery applications. We believe that the demonstrations shown in this paper provide a promising strategy to investigate highly efficient metal-free catalysts for advanced energy devices. |
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