玉米芯基碳点电化学法制备及其储钠性能

Preparation of carbon dots from carbonized corncobs by electrochemical oxidation and their application in Na-batteries

碳点(CDs)是一种新兴的碳纳米材料,因其高比表面积、良好的分散性、丰富的表面官能团、低生物毒性和光致发光特性而受到了研究者的广泛关注。然而,低成本、大规模和绿色合成CDs仍面临挑战。本工作基于生物质玉米芯特殊的天然孔隙结构,经直接炭化制备具有定向、贯通微纳米孔道的多孔三维电极材料,在毛细作用下电解液可以充满整个电极材料,内外表面同时发生电化学氧化,实现高效制备CDs。在1 A恒电流下,每克电极材料制备CDs速率达到了79.83 mg h^(-1)。将制备的CDs与氧化石墨烯(GO)水热复合得到复合气凝胶CDs/rGO材料,经热处理后应用于钠离子电池。在1 A g^(-1)下循环1 000圈仍保持263.3 mAh g^(-1)的容量。本研究工作采用生物质玉米芯高效制备CDs,为CDs的大规模绿色制备和应用提供了新的途径和思路。

Carbon dots(CDs)have attracted increasing attention due to their high specific surface area,good dispersion,abundant surface functional groups,low biotoxicity and photoluminescence.However,their preparation on a large-scale is still a great challenge because of the high cost and environmental problems,and this seriously limits their practical applications.Herein,carbonized corncobs were used as the starting material for the preparation of the CDs by electrochemical oxidation.Their natural porous structures with well-developed channels allow the electrode to be filled with electrolyte,and the electrochemical oxidation takes place both on the inside and outside surfaces of the carbonized corncob,achieving a CD output of 79.8 mg h^(−1) per gram of electrode material at 1 A.The CDs were combined with graphene oxide(GO)to produce CD/rGO composite aerogels by a hydrothermal method.After heat treatment at 600°C,the materials obtained were used as the anode in a sodium ion battery,which had a capacity of 263.3 mAh g^(−1) after 1000 cycles at 1 A g^(−1).This work suggests a new way to prepare CDs and possibly expand their range of application.