High-Throughput Experimentation for Selective Growth of Small-Diameter Single-Wall Carbon Nanotubes Using Ru-Promoted Co Catalysts
High-Throughput Experimentation for Selective Growth of Small-Diameter Single-Wall Carbon Nanotubes Using Ru-Promoted Co Catalysts
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DOI：
10.1021/acs.chemmater.2c00347
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发表时间：
2022-05-24
影响因子：
8.6
通讯作者：
Amama, Placidus B.
中科院分区：
文献类型：
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作者：
Everhart, Brian M.;Rao, Rahul;Amama, Placidus B.
小直径单壁碳纳米管（SWCNTs）在需要大于1ev的电子带隙的各种应用中是理想的。在这里，我们使用自主研究系统（ARES）？？自动化，高通量，激光诱导化学气相沉积系统与在situRaman光谱反馈？？研究Ru对助催化剂在小直径SWCNTs生长中的促进作用。通过在ARES中进行200多次不同原料的生长实验和广泛的多激发拉曼光谱表征，我们证明，与Co相比，Ru促进的Co催化剂在750℃下的选择性几乎是小直径SWCNTs（直径小于1 nm）的两倍。在800至850℃的高温下，Ru稳定了Co催化剂纳米颗粒，并将小直径SWCNTs的选择性提高了近三倍。结果表明，SWCNTs的直径不仅取决于催化剂的性质，还取决于原料的类型，对小直径SWCNTs的选择性降低顺序如下：乙烯b>乙炔> fs - gp（费托合成气体产物混合物）。用13和55个原子的coxruy团簇（Ru含量从0到22%）进行密度泛函理论计算，发现团簇内聚能（EC）随着Ru含量的增加而增加，而与团簇中Ru原子的确切位置无关。这些发现表明，随着Ru含量的增加，熔融温度升高，原子迁移率降低，这与我们的Co催化剂中存在10%的Ru，增加烧结阻力，小纳米颗粒的稳定性以及观察到的对小直径SWCNTs的高选择性是一致的
Small-diameter single-wall carbon nanotubes(SWCNTs) are desirable in a variety of applications requiringelectronic band gaps greater than 1 eV. Here, we utilize theAutonomous Research System (ARES)???an automated, high through-put, laser-induced chemical vapor deposition system with in situRaman spectral feedback???to study the role of Ru promotion of Cocatalysts in the growth of small-diameter SWCNTs. By performingover 200 growth experiments in ARES with different feedstocks andextensive multiexcitation Raman spectroscopic characterization, wedemonstrate that the Ru-promoted Co catalyst nearly doubles theselectivity of small-diameter SWCNTs (diameters below 1 nm) at 750 degrees C in comparison to Co. At higher temperatures between 800 and 850 degrees C, Ru stabilizes Co catalyst nanoparticles and increases the selectivityof small-diameter SWCNTs by almost a factor of three. Results revealthat SWCNT diameters are not only dependent on catalyst properties but also on the type of feedstock as selectivity toward small-diameter SWCNTs decreases in the following order: ethylene > acetylene > FTS-GP (Fischer-Tropsch synthesis gaseous productmixture). Density functional theory calculations with 13 and 55 atom CoxRuyclusters (ranging from 0 to 22% Ru content) revealincreases in cluster cohesive energies (EC) with Ru content, irrespective of the exact location of Ru atoms in the clusters. As thesefindings are indicative of increases in melting temperature and reduction in atom mobility with Ru content, they are consistent withthe presence of similar to 10% Ru in our Co catalyst, increasing sintering resistance, stability of small nanoparticles, and the observed highselectivity toward small-diameter SWCNTs