双峰孔分布薄壁中孔碳的便捷制备

以廉价的γ-氧化铝为模板制备薄壁中孔碳材料,且可在制备过程中方便地对碳材料的孔结构、微孔率等参数进行调控.以原位聚合的酚醛树脂为碳源取代蔗糖,简化了制备流程.制得的碳材料不仅可以较好地复制氧化铝模板的孔结构,且比表面积比以蔗糖为碳源的样品显著提高.在此基础上,选用模板堆积孔径与模板自身直径差异较大的长棒状氧化铝为模板,成功地以一种模板、经过一次聚合-碳化过程制备出了具有双峰孔分布(PSD)结构的薄壁碳材料,两个峰分别位于4 nm附近的较小中孔区和13 nm附近的较大中孔区.此外,所得碳材料的比表面积(>1800 m2·g-1)和孔容(>4.5 cm3·g-1)均很高,而微孔率却较低,具有优异的中孔特性.将所得碳材料用作电化学电容器的电极,电容可达200 F·g-1,且当电流密度从0.1 A·g-1升至1.0 A·g-1时,比电容仅衰减10%,表现出良好的电容性能.

Facile Synthesis of Bimodal Mesoporous Carbon with Thin Pore Walls

Mesoporous carbon materials are required for application in various areas.In our previous work,we successfully prepared mesoporous carbon with thin pore walls using inexpensive γ-alumina as a template and sucrose as the carbon source,and proposed a mechanism for the synthetic process.In this work,other carbon source was explored to improve the synthetic process and obtain a better understanding of the synthetic mechanism.Compared with sucrose,phenolic resin generated in situ as the carbon precursor can form a complete and robust carbon layer on the template surface in one polymerization and carbonization procedure,simplifying the synthetic process.In addition,the specific surface areas of the carbon materials were greatly increased when phenolic resin was used as the carbon precursor.According to the proposed synthetic mechanism,the mesopores of the carbon materials had two sources:the removal of template particles,and the original pores of the template.When the size of template pores differed significantly from that of the template particles,the obtained carbon materials possessed a bimodal pore size distribution(PSD) at about 4 and 13 nm.In this work,carbon material with a bimodal PSD in the mesopore range was obtained when thin,rod-like alumina was used as the template.The carbon materials possessed ultra large specific surface area(>1800 m 2·g-1) and pore volume(>4.5 cm 3·g-1),so they were used as electrodes for electric double-layer capacitors.Cyclic voltammograms were nearly rectangular even at a high sweep rate(50 mV·s-1),and the capacitances were relatively high(about 200 F·g-1).When the current density was increased from 0.1 A·g-1 to 1.0 A·g-1,the decrease in specific capacitance was only 10%.