Cobalt-based Fischer–Tropsch catalysts supported on different types of N-doped carbon nanotubes

Abstract

N-doped nanocarbons are promising materials for metal-free and supported catalysts. Three types of N-doped carbon nanotubes (N-CNTs) were synthesized by chemical vapor deposition (CVD), by oxidation of the CVD produced N-CNTs with nitric acid, and by post-doping of oxidized undoped CNTs with ammonia. Cobalt catalysts with 20[Formula: see text]wt.% loading supported on N-CNTs were tested in the Fischer–Tropsch synthesis. Oxidized N-CNTs containing pyridone groups demonstrated the best stabilization of cobalt nanoparticles. The catalyst on this support showed the highest selectivity towards [Formula: see text] hydrocarbons. The performance of the catalyst supported on CVD N-CNTs was the worst because of the large variation in cobalt particle size and low reduction degree. The catalysts supported on post-doped CNTs demonstrated the best activity, but high methane selectivity because of the low Co particle size ([Formula: see text][Formula: see text]nm).