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利用高压容积法测定多壁碳纳米管(MWCNTs)及钾盐修饰的相应体系(K+-MWCNTs)的储氢容量,并用程序升温脱附(TPD)方法表征研究氢气在MWCNTs基材料上的吸附-脱附特性.结果表明,在经纯化MWC-NTs上,室温、9.0MPa实验条件下氢的储量可达1.51%(质量分数);K+盐对MWCNTs的修饰对增加其储氢容量并无促进效应,但相应化学吸附氢物种的脱附温度有所升高;K+的修饰也改变了MWCNTs表面原有的疏水性质.在低于723K的温度下,H2/MWCNTs体系的脱附产物几乎全为氢气;773K以上高温脱附产物不仅含H2,也含有CH4、C2H4、C2H2等C1/C2烃混合物;H2/K+-MWCNTs储氢试样的脱附产物除占主体量的H2及少量C1/C2烃混合物外,还含水汽,其量与吸附质H2源水汽含量密切相关.H2在碳纳米管基材料上吸附兼具非解离(即分子态)和解离(即原子态)两种形式.
The hydrogen storage capacity of multi-walled carbon nanotubes (MWCNTs) and potassium salt-modified corresponding systems (K + -MWCNTs) was measured by high pressure voltammetry. The adsorption of hydrogen on MWCNTs was investigated by temperature programmed desorption (TPD) The results showed that the hydrogen storage capacity reached 1.51% (mass fraction) at room temperature and 9.0MPa under the conditions of purified MWC-NTs. The modification of MWCNTs by K + salt did not promote the hydrogen storage capacity , But the desorption temperature of the corresponding chemisorbed hydrogen species increased. K + modification also changed the original hydrophobic property of MWCNTs. At temperatures below 723K, the desorption products of the H2 / MWCNTs system were almost all hydrogen ; More than 773K high temperature desorption products not only contain H2, but also contain C1 / C2 hydrocarbon mixtures such as CH4, C2H4, C2H2; H2 / K + -MWCNTs hydrogen desorption samples in addition to the main product of H2 and a small amount of C1 / C2 hydrocarbons Mixture, but also contains water vapor, the amount of which is closely related to the water vapor content of the H2 source of the adsorbate.H2 adsorbs both the non-dissociated (ie, molecular) and the dissociated (ie, atomic) forms on the carbon nanotube-based material.