Preparation of lignin-based carbon nanotubes using micelles as soft template

As a natural renewable biomass resource with abundant reserves, lignin has broad prospects in the preparation of lignin-based carbon fibers and lignin-based carbon nanospheres. However, it remains a challenge to prepare carbon nanotubes using lignin as a carbon source. Herein, a feasible method for the preparation of lignin-based carbon nanotubes (L-CNTs) using lignin as the carbon source based on mobile chemical vapor deposition is proposed. First, lignin-based micelles were used as a soft template to prepare a catalyst, and then L-CNTs were synthesized from gaseous products generated by lignin pyrolysis. The results reflected the important roles of the catalyst preparation process, the concentration of catalyst precursor, and the synthesis temperature on the morphologies and structures of the L-CNTs. By adjusting the reaction conditions, L-CNTs with diameters ranging from 10 to 110 nm and lengths ranging from 1 to 6 µm were obtained. The synthesized L-CNTs were mainly multi-walled carbon nanotubes, of which the crystal layer spacing was 0.35 nm, with a good graphitization degree and thermal stability. This synthesis strategy will provide a new method for the high-value utilization of lignin.