Carbon nanotubes prepared by the chemical vapor deposition method have extraordinary properties in mechanical strength [1,2], thermal and electrical conductivity  etc. and can be used as additives, catalysts and nanometer reactors etc. [1,4]. For further research on CNTs and the ultimate commercialization of CNTs, a cheap catalyst, a simple synthesis method and a cheap carbon source are necessary for their preparation at low cost. Carbon sources including hydrocarbons and CO with high purity (higher than 99.9%) have been widely adopted to make CNTs in previous studies [1,4–8]. These pure carbon sources are very expensive and have limited supply, compared to cheaper fuels such as natural gas, sour natural gas liquid (NGL) and water gas. Since these contain sulfur of a few to several hundred ppm, which will poison the catalyst
heavily, few reports currently exist on using sour NGL
or natural gas directly. In this contribution, we report that direct synthesis of CNTs can be achieved from the decomposition of the sour NGL
containing sulfur of 13 ppm by a Fe /Mo/Al2O3 catalyst.