Shi Wenbo, Peng Yue, Steiner Stephen A, Li Junhua, Plata Desiree L
Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, 06520, USA.
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
Small. 2018 Mar;14(11):e1703482. doi: 10.1002/smll.201703482. Epub 2018 Jan 16.
The equimolar C H -CO reaction has shown promise for carbon nanotube (CNT) production at low temperatures and on diverse functional substrate materials; however, the electron-pushing mechanism of this reaction is not well demonstrated. Here, the role of CO is explored experimentally and theoretically. In particular, C labeling of CO demonstrates that CO is not an important C source in CNT growth by thermal catalytic chemical vapor deposition. Consistent with this experimental finding, the adsorption behaviors of C H and CO on a graphene-like lattice via density functional theory calculations reveal that the binding energies of C H are markedly higher than that of CO , suggesting the former is more likely to incorporate into CNT structure. Further, H-abstraction by CO from the active CNT growth edge would be favored, ultimately forming CO and H O. These results support that the commonly observed, promoting role of CO in CNT growth is due to a CO -assisted dehydrogenation mechanism.
等摩尔的C₂H₂-CO反应已显示出在低温下以及在多种功能性衬底材料上生产碳纳米管（CNT）的潜力；然而，该反应的电子推动机制尚未得到充分证明。在此，通过实验和理论探索了CO的作用。特别是，对CO进行¹³C标记表明，在热催化化学气相沉积法生长碳纳米管的过程中，CO并非重要的碳源。与这一实验发现一致，通过密度泛函理论计算得出的C₂H₂和CO在类石墨烯晶格上的吸附行为表明，C₂H₂的结合能明显高于CO的结合能，这表明前者更有可能融入碳纳米管结构。此外，CO从活性碳纳米管生长边缘夺取氢会更有利，最终形成CO₂和H₂O。这些结果支持了在碳纳米管生长过程中普遍观察到的CO的促进作用是由于CO₂辅助脱氢机制。
