Systematic review of catalyst nanoparticles synthesized by solution process: towards efficient carbon nanotube growth

Nano-field research has been expanded rapidly since those tiny materials such as carbon nanotubes (CNTs), cobalt catalyst and iron catalyst can give huge impact to the application products with their extraordinary properties. The scientific discovery of these materials can be defined as a magic key to solve the raw materials shortage and unlock the limitation performance of the devices. CNTs have been found to be one of the new nanomaterials that can improve different kind of devices’ performance. CNT can be grown on the substrates with the presence of active metal catalysts. Since small metal catalyst particles (diameter <10 nm) are crucial in growing CNTs, the deposition method of metal catalyst on the substrates has been studied. The optional processes using solutions to produce catalyst nanoparticles will be discussed in this review. Sol–gel process along with spin coating is the most suitable deposition method with low cost of production and the easiness to control particle size deposited on the substrates.