酚醛树脂基整体式多级孔炭制备及孔结构调控

Preparation and pore structure control of resorcinol-formaldehyde resin-based monolithic hiearchical porous carbon

采用Stber法,以间苯二酚、甲醛为原料,HCl为催化剂,乙醇和水为混合溶剂,制备了具有纳微米结构整体式间苯二酚甲醛树脂,以之为前驱体,在Ar气氛中,经900℃炭化2 h,制备了整体式微孔-介孔-大孔多级孔炭.采用傅里叶红外光谱仪(FTIR)、热重分析仪(TG)、扫描电子显微镜(SEM)、X-射线衍射仪(XRD)、透射电镜(TEM)及N_2气等温吸-脱附实验,对多级孔炭及其前驱体组成、形貌和孔结构进行了表征.结果表明:通过简单调控间苯二酚和甲醛用量、醇水比可制备比表面高达626 m^2/g整体式多级孔炭,实现了酚醛树脂裂解炭在形貌和孔径分布可调(在微孔、介孔和大孔范围内);随着间苯二酚和甲醛用量增加,裂解炭孔径在大孔区域分布强度降低;随着醇水比增大,酚醛树脂裂解碳微球粒径增大,裂解炭由离散相微球逐渐转变为连续相;通过增大醇水比,可有效增强酚醛树脂交联密度,降低酚醛树脂裂解炭孔径在微孔范围分布强度.

To accomplish the controllable preparation of resorcinol-formaldehyde resins-based monolithic hierarchical porous carbon,monolithic nano and micro-structures of resorcinol-formaldehyde resins were prepared via Stber method,using resorcinol and formaldehyde as raw materials,HCl as catalyst,and the mixture of ethanol and water as solvent. The prepared resorcinol-formaldehyde resins were pyrolyzed at 900 ℃ for 2 h in Ar gas atmosphere to produce the monolithic hiearchical micro-/meso-/macro-porous carbons. The composition,morphology and pore structure of the hierarchical porous carbons and their precursors were characterized by Fourier transform infrared spectroscopy（FTIR）,thermogravimetric analyzer（TG）,scanning electron microscopy（SEM）,X-ray diffraction（XRD）,transmission electron microscopy（TEM） and N2 gas adsorption-desorption experiment. The results showed that the morphology and hierarchical pore size distribution in micropore,mesopore and macropore ranges of the monlithic carbons,which had a high specific surface area of 626 m^2/g,can be controlled by the simple regulation of resorcinol and formaldehyde content,and the volume ratio of alcohol to water. The distribution of pore size decreased in the macropore region with increasing the content of resorcinol and formaldehyde. The particle size of the pyrolylic carbon microspheres increased with increasing the ratios of alcohol to water by volume. The discrete phase of the pyrolytic carbon microspheres gradually transformed into continuous carbonous phase by increasing the volume ratio of alcohol to water. The enhanced crosslinking density of resorcinol-formaldehyde resin prepared by a high volume ratio of alcohol to water resulted in the decrease in the micropore sized distribition.