Synthesis of directly spinnable carbon nanotube carpets via the oxidative dehydrogenation reaction of C2H2-CO2

Continuous fibers spun directly from aligned carbon nanotube (CNT) carpets are very interesting for many applications. However, the synthesis of spinnable CNTs carpets remains a challenge because not every carpet is spinnable and the spinnability is strongly influenced by the precise CNTs growth condition. Therefore, developing a robust and scalable process that allows us growing CNT carpets with high and reproducible spinnability is highly desirable. In this work, the oxidative dehydrogenation reaction of C2H2-CO2 was used, for the first time, for the synthesis of spinnable CNT carpets. This chemical vapor deposition (CVD) process involves equimolar mixture of C2H2/CO2 and leads to high CNTs yield at relatively low growth temperature and on various substrate materials. The spinnability of CNT carpets was systematically studied by varying the CVD parameters, including catalyst, reaction time and cooling rate. By using a flat substrate without any exposure to air, 10 min reaction time in C2H2-CO2 diluted by H2 and by slow cooling after the hydrocarbon gas flow stopped, highly spinnable CNT carpets with a 300 μm thickness were obtained, which can be spun into fibers up to 50 cm. The knowledge gained in this study represents a step towards a controllable, reproducible and up-scalable process for spinnable CNT carpets synthesis.status: publishe