Increase of adsorption capacity of single-walled carbon nanotubes by opening holes for application in cryopumps
Increase of adsorption capacity of single-walled carbon nanotubes by opening holes for application in cryopumps
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DOI：
10.1007/s11051-022-05467-7
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发表时间：
2022-04
影响因子：
2.5
通讯作者：
Xiaolong Xu;Weihang Tan;K. Nie;Jiahao Xu;Ningning Ji;Zhenqi Chang
中科院分区：
文献类型：
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作者：
Xiaolong Xu;Weihang Tan;K. Nie;Jiahao Xu;Ningning Ji;Zhenqi Chang
在国际热核聚变实验堆（ITER）中，具有大比表面积的椰壳活性炭（CSAC）被用于环形低温泵中，用于吸收氦和杂质气体中的氢同位素。然而，CSAC具有不规则的形态，并含有高水平的杂质，寻找更多的氚兼容的吸附材料是必要的。单壁碳纳米管（SWCNTs）具有纯度高、形貌规则、比CSAC更小的SSA。在这项研究中，通过在空气中缓慢氧化打开单壁碳纳米管，以增加其SSA。评价了处理后的单壁碳纳米管（t-SWCNTs）作为氚兼容环形低温泵吸附材料的潜力。结果表明，在不改变碳纳米管基本形貌和引入杂质的情况下，空气中缓慢氧化可显著提高单壁碳纳米管的比表面积。目标温度为500 °C的T-SWCNT具有最大的SSA，其大于CSAC。目标温度为500 °C的t-SWCNTs的杂质含量低于CSAC，特别是对后续氚厂氢同位素分离过程有害的杂质（P、S、H）明显低于CSAC。结果表明，T-SWCNTs是一种新的低温吸附剂在氚兼容的环面低温泵的潜在候选人。
In International Thermonuclear Experimental Reactor (ITER), coconut-shell activated carbon (CSAC) with a large specific surface area (SSA) has been used in the torus cryopumps to absorb hydrogen isotopes with helium and impurity gases. However, CSAC has irregular morphology and contains high levels of impurities; search for more tritium-compatible adsorption materials is necessary. Single-walled carbon nanotubes (SWCNTs) have higher purity and more regular morphology, and less SSA than CSAC. In this study, opening SWCNTs via slow oxidation in air was performed to increase their SSA. The potentials of treated SWCNTs (t-SWCNTs) as adsorption materials in the tritium-compatible torus cryopump were evaluated. The results show that the SSA of SWCNTs has significantly increased by slow oxidation in air without changing their basic morphology and introducing impurities. T-SWCNTs with the target temperature of 500 °C have the largest SSA, which is larger than CSAC. The impurity contents of t-SWCNTs with target temperature of 500 °C are less than that of CSAC, especially the impurities (P, S, H) harmful to hydrogen isotope separation process in subsequent tritium plants are significantly less than that of CSAC. The results demonstrate that T-SWCNTs are potential candidates for a new cryosorbent in the tritium-compatible torus cryopump.