Highly dispersed cobalt on N-doped carbon nanotubes with improved Fischer–Tropsch synthesis activity

•The bamboo-like structure of N-doped CNTs disappeared after acid treatment.•N doping and acid treatment improved Co dispersion inside the tubes of the NCNTs.•Co/A-NCNTs had higher CO conversion for FTS than Co/A-CNTs.•Co/A-NCNTs produced a narrow distribution of low carbon number hydrocarbons.

N-doped carbon nanotubes (NCNTs) were used as the support for a Co catalyst (Co/A-NCNTs). After acid treatment, the bamboo-like structure of the NCNTs disappeared and more defects were formed on the surface of the NCNTs; however there was little change in the inner diameter and N content of the nanotubes. This resulted in an improved dispersion of Co inside the cavities of the NCNTs. The Co/A-NCNT catalyst was compared with Co supported on acid treated CNTs, and the Co/A-NCNT catalyst had a smaller surface area and for Fischer–Tropsch (FT) synthesis, it had a higher CO conversion with producing a narrower distribution of low carbon number hydrocarbons. The high Co dispersion in the Co/A-NCNTs is the main reason for the improved FT synthesis performance.

Graphical abstractN-doped carbon nanotubes (NCNTs) were used as the support for a Co catalyst. After acid treatment, the bamboo-like structure of the NCNTs disappeared. Highly dispersed cobalt particles inside the tubes of acid treated NCNTs (A-NCNTs) were obtained because of the N doping and acid treatment. Compared with acid treated non-N-doped CNTs supported Co catalyst (Co/A-CNTs), the Co catalyst supported on A-NCNTs (Co/A-NCNTs) had a higher CO conversion with producing a narrower distribution of low carbon number hydrocarbons for FT synthesis.Figure optionsDownload full-size imageDownload as PowerPoint slide