Growth of Carbon Nanotubes by Pyrolysis of Thiophene

The synthesis of carbon nanotubes (CNTs) by cobalt-catalyzed pyrolysis of thiophene has been investigated and optimized. The yield and the morphology of the synthesized product are highly sensitive to the experimental conditions. A synthesis temperature of 1000 °C is required for the decomposition of thiophene. The morphology and microstructure of the product are controlled by the thiophene vapor concentration and flow rate. High concentration of thiophene vapor deactivates the catalyst and results in the formation of carbon nanofibers or short CNTs with bad graphitization; the optimum thiophene concentration for CNTs growth is around 0.76−1%. Thiophene vapor at high flow rate produces Y-junction and multibranched CNTs. Three formation routes are proposed to illuminate the growth mechanism of the branched CNTs.