摘要
生物质材料是一种来源丰富、廉价易得的可再生资源,通过在生物质材料中构筑多层级结构制备生物质碳材料是目前吸波材料领域研究的热点。为制备轻质、宽频、高效的生物碳基吸波材料,以龙眼壳为原料,通过活化碳化的方式制备龙眼壳多孔碳材料(LSPC),通过X-射线衍射、拉曼光谱、扫描电镜等表征多孔碳材料的微观结构,并采用矢量网络分析仪对其吸波性能进行分析,考察了磷酸(H3PO4)、氢氧化钾(KOH)和氧化锌(ZnCl_(2))对龙眼壳多孔碳材料结构和吸波性能的影响。结果表明:活化使得龙眼壳多孔碳结晶度下降、缺陷增多,形成了较多的异质界面和活化中心,增强了材料的极化损耗。与未活化的龙眼壳多孔碳相比,H3PO4活化处理使得多孔碳材料的孔壁变薄、孔结构更为明显;KOH活化多孔碳材料不仅保留了龙眼壳连续的孔结构,而且孔壁出现了类似脊椎的波浪起伏结构;ZnCl_(2)活化制得的龙眼壳多孔碳材料仅在原有的光滑截面形成许多小孔;综合分析表明,活化处理改善了龙眼壳多孔碳材料的吸波性能,其中以氢氧化钾活化制备的龙眼壳多孔碳材料吸波性能最佳,其反射损耗达到-43.57 dB,分别是LSPC-H3PO4的2.03倍和LSPC-ZnCl_(2)的3.02倍;活化处理不同程度地改善了龙眼壳多孔碳材料的有效吸收带宽。对微观形貌关联的电磁损耗行为分析表明,活化促进了龙眼壳多孔碳材料中多层级孔结构的生成,有效降低了龙眼壳多孔碳材料的有效介电常数,改善了材料的阻抗匹配;同时,龙眼壳多孔碳材料可通过传导损耗、偶极极化、界面极化、多重反射等多重损耗机制衰减电磁波。
Biomass-derived porous carbon has drawn extensive attention in the microwave absorbing materials(MAMs)due to the advantages of extensive sources,low-cost,sustainability and tailorable structure.Aimtolight-weight bio-mass-derived MAMs with high attenuation capacity over wide frequency range,longan shell-based porous carbon mate-rial(LSPC)was prepared by activated carbonization by using different activators,namely phosphoric acid(H3PO4),potassium hydroxide(KOH)and zinc chloride(ZnCl_(2)).Influence of activation on the microstructure,morphology and microwave absorbing performance of resulted porous carbon materials were systematically investigated by applying X-ray diffraction,Raman spectroscopy,scanning electron microscopyvector network analyzer.Results indicate that activation induced more amorphous regions and defects,thus forming more heterogeneous interface and polarization centers conducing to the dielectric loss.Compared with LSPC with thick and smooth skeletons,activated LSPC materi-als showed hierarchical structures with different scale pores.While LSPC-H3PO4 exhibited thinner wall of pores and LSPC-ZnCl_(2)showed smaller pores on the skeleton,LSPC-KOH depicted vertebra-like hierarchical structure.Activation improved the microwave absorbing performance,and LSPC-KOH showed the best microwave capacity,with minimum reflection loss of‒43.57 dB,which was 2.03 times and 3.02 times higher than that of LSPC-H3PO4 and LSPC-ZnCl_(2),respectively.Moreover,activation broadened the effective absorption bandwidth of LSPC to varying degrees.Analysis of structure-associated electromagnetic loss behavior implies that hierarchical structure,dipolar/interfacial polarization and multiple reflection greatly contribute to the balanced impedance matching and attenuation capacity,thus improving the microwave absorption performance of activated LSPC materials.
作者
王兵兵
黄乐
龙爱春
廖禄生
王蕊
赵艳芳
赵鹏飞
WANG Bingbing;HUANG Le;LONG Aichun;LIAO Lusheng;WANG Rui;ZHAO Yanfang;ZHAO Pengfei(Agricultural Product Processing Research Institute,Chinese Academy of Tropical Agricultural Sciences/Guangdong Key Labo-ratory of Natural Rubber Processing,Zhanjiang,Guangdong 524001,China;Material Science and Engineering institute,Hainan University,Haikou,Hainan 570228,China;Hainan Key Laboratory of Natural Rubber Processing,Zhanjiang,Guangdong 524001,China)
出处
《热带作物学报》
CSCD
北大核心
2024年第1期169-175,共7页
Chinese Journal of Tropical Crops
基金
现代农业产业技术体系专项资金项目(No.CARS-33)
海南省自然科学基金项目(No.521MS082)
中央级公益性科研院所基本科研业务费专项资金项目(No.1630122022011)。
关键词
龙眼壳
多孔碳
电磁损耗
吸波性能
longan shell
porous carbon
electromagnetic loss
microwave absorbing performance
