Controlled synthesis of carbon nanocoils with selective coil diameters and structures by optimizing the thickness of catalyst film

Carbon nanocoils (CNCs) with selective coil diameters and structures have been synthesized by chemical vapor deposition using Sn/Fe binary catalyst films. CNCs, carbon nanofibers and irregular carbon nanowires could be selectively obtained by changing the thickness of the catalyst film. It is found that the coil diameters of CNCs gradually decrease with a decrease in the thickness of the catalyst films within a certain range, indicating that the coil diameters of CNCs can be effectively controlled by adjusting the thickness of Sn/Fe catalyst films. The morphology of the CNCs tends to change from spring-like to plait-like, and the graphitization degree of the CNC increases when their diameters are reduced. Our results provide important guidelines for the controlled synthesis of CNCs with selective coil diameters and selective structures by optimizing the catalyst film thickness.