Tungsten-based ternary catalysts for selective growth of single-walled carbon nanotubes

Single-walled carbon nanotubes (SWCNTs) with controlled diameters ranging from 1.5 to 3 nm were synthesized through a supported catalytic chemical vapor deposition (CCVD) process using an Fe-Mo-W ternary catalyst system. Tungsten in the ternary catalyst played a crucial role in maintaining catalyst size while the temperature was being increased for synthesis, ensuring stability under high temperature conditions. Through the use of the ternary catalyst, we developed a method to control the size of the nanocatalyst supported by mesoporous magnesium oxide. The impregnated ternary metal catalysts within the mesopores of the support facilitated the uniform growth of small-diameter SWCNTs. The tungsten-containing intermetallic nanocatalyst proved to be stable by preventing the agglomeration of catalyst particles during the high temperature process, mitigating Ostwald ripening and promoting the controlled growth of SWCNTs. This catalytic system enabled the precise synthesis of SWCNTs with tunable diameters, offering the potential for direct control of their properties and providing greater flexibility for various applications.