H_2在K^0-MWCNTs上储存和吸附/脱附特性研究  

Study of Storage and Adsorption/Desorption Characteristics of H_2 on MWCNTs Modified by Metal Potassium

作　　者：武小满[1] 王毅[1] 董昆明[1] 周金梅[1] 林国栋[1] 张鸿斌[1] 

机构地区：[1]厦门大学化学化工学院固体表面物理化学国家重点实验室,厦门361005

出　　处：《化学学报》2005年第6期484-490,F007,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(No.50072021);福建省自然科学基金(No.2001H017)资助项目.

摘　　要：利用高压容积法辅以卸压升温脱附排水法,测定金属K修饰多壁碳纳米管对H2的吸附储存容量.结果表明,在室温(25℃),7.25MPa实验条件下,x%K0-MWCNTs(x%=30%～35%,质量百分数)对H2的吸附储存容量可达3.80wt%(质量百分数),是相同条件下单纯MWCNTs氢吸附储量的2.5倍;室温下卸至常压的脱附氢量为3.36wt%(占总吸附氢量的～88%),后续升温至673K的脱附氢量为0.41wt%(占总吸附氢量的～11%).利用LRS和H2-TPD-GC/MS等谱学方法对H2/K0-MWCNTs吸附体系的表征研究表明,H2在K0-MWCNTs上吸附存在非解离(即分子态)和解离(即原子态)两种吸附态;在≤723K温度下,H2/K0-MWCNTs体系的脱附产物几乎全为H2气;723K以上高温脱附产物不仅含H2,也含有CH4,C2H4和C2H2等C1/C2-烃.Storage capacity of H-2 in a kind of potassium-modified multiwalled carbon nanotubes, K-0-MWCNTs, was measured by using high-pressure volumetric method combined with desorption water-displacement method. It was experimentally shown that appropriate incorporation of a certain amount of metallic potassium into the MWCNTs could significantly increase the storage capacity of hydrogen. Under conditions of 7.25 MPa and ambient temperature, H-2 uptake of 3.8 wt% could be achieved by the x%K-0-MWCNTs (x%=30%-35%, mass percentage), which was 2.5 times as high as that by the KO-free MWCNTs under the same conditions. It was also indicated that adsorption of 99% of the H2 was reversible, and that 88% of the stored hydrogen (equalling storage capacities of 3.36 wt%) could be desorbed while the pressure was relieved to atmospheric pressure and similar to 11% of the stored hydrogen (equalling storage capacities of 0.41 wt%) was desorbed in the following process of elevating temperature from room temperature to 673 K. The Raman-spectroscopic and TPD-MS/GC investigations of the H-2/K-0-MWCNTs adsorption systems showed that adsorption of H-2 on the MWCNTs could occur in associative and dissociative forms, with the observed v(s)(C-H) for CH2, v(C-H) for CH and v(H-H) for H-2 (a) at 2856, 3228 and 3946 cm(-1), respectively, and that H-2 Was the predominant products desorbed at temperatures lower than 723 K, whereas in addition to H-2, light hydrocarbons such as CH4, C2H4, C2H2, etc. were also involved in the products desorbed at temperatures higher than 723 K.

关 键 词：脱附 C2H2 原子态 TPD 吸附 谱学 解离 产物 升温 C2H4 

分 类 号：O647.3[理学—物理化学]