多壁碳纳米管/Mg-MOF-74的制备及其CO_2吸附性能

由于MOFs材料在潮湿环境下表现出较低的CO_2吸附性能和稳定性能。采用化学修饰法将多壁碳纳米管(MWCNTs)羧基化,采用溶剂热法合成多壁碳纳米管/Mg-MOF-74复合材料(CNT@Mg-MOF-74),使用粉末X射线衍射、傅里叶变换红外光谱、热重分析、扫描电镜、氮气物理吸附等表征手段考察材料的结构和形貌。考察了MWCNTs,Mg-MOF-74,CNT@Mg-MOF-74在25℃、常压下对CO_2的吸附效果,CNT@Mg-MOF-74的循环再生性能以及Mg-MOF-74和CNT@Mg-MOF-74在潮湿环境下(温度28℃,相对湿度72%)的结构稳定性。结果表明,MWCNTs的掺杂并不影响Mg-MOF-74的结构和形貌。CNT@Mg-MOF-74相比Mg-MOF-74具有更好的疏水能力。CNT@MgMOF-74在25℃、常压下对CO_2的饱和吸附量可达79.88 mg/g,相比Mg-MOF-74吸附量(CO_2饱和吸附量为59.75mg/g)增加了34%,5次循环再生率均为100%,而且CNT@Mg-MOF-74相比Mg-MOF-74在潮湿环境下具有更好的结构稳定性。

Preparation of MWCNTs/Mg-MOF-74 Hybrid Composite and the Performance in CO2Adsorption

Limit applications have been existed because hygroscopic property of MOFs,and atmosphericmoisture also cau-ses MOFs instability and low gases adsorption capacity. In order to overcome these problems, acid-functionalized multi-walled carbon nanotubes(MWCNTs) incorporated Mg-MOF-74 composite(CNT@Mg-MOF-74) has been successfully syn-thesized and characterized by XRD,FT-IR,TGA,SEM and BET analysis. Meanwhile, the performance of Mg-MOF-74, MWCNTs and CNT@Mg-MOF-74 in CO2adsorption were investigated under 25 ℃ and ambient pressure. Tested regenera-tionperformance of CNT@Mg-MOF-74 and the moisture stability of Mg-MOF-74 and CNT@Mg-MOF-74 in moisture envi-ronment(at 33% relative humidity and 23 °C). The result indicating that CNT@Mg-MOF-74 obtained has the same crys-tal structure as that of virgin Mg-MOF-74,and has the same morphology both of the virgin Mg-MOF-74 and MWCNTs,but exhibited a much greater CO2adsorptioncapacity(increased from 59.75 to 79.88 mg/g,about a 34% increase in CO2stor-age capacity at 25 ℃ and ambient pressure), and an improved stability in moist conditions. The regeneration rate can maintain 100% in 5 repeat cycles.