Optimization of carbon nanotubes synthesis via pyrolysis over Ni/Al2O3 using response surface methodology

Owing to the rapid expansion of preparing a low-cost and pure carbon nanotubes (CNTs) from large available raw materials as cheap carbon precursors and catalyst depositions via chemical vapor deposition process, Algerian condensate gas over Ni/Al2O3 was used in this study. Response surface methodology was utilized to assess and optimize the preparation parameters. Synthesis of CNTs was studied as a function of three independent parameters: catalyst/condensate-gas weight ratio (5-10 wt %), synthesis time (30-120 min) and temperature (700-1000 degrees C). Optimum conditions for the CNTS-synthesis were found to be 5%, 112 min and 1000 degrees C, for catalyst/condensate gas mass ratio, synthesis time and temperature, respectively. Under these conditions, Raman spectrum indicates high values of (IG/ID), which means high-quality CNTs. Examination by SEM and HRTEM revealed that the CNTs grown under optimum conditions had diameters of 10 nm. The carbon yield predicted at the optimum process conditions was 81.76%. Conclusively, the pure and uniformed CNTs can be produced with high yield by the conversion of available-cheap resources via CVD-method. This method is practical, realistic, feasible in industrial scale and thus can reduces the cost manufacture of CNTs, which may help increase the impact of these remarkable materials in many fields.

Automated summary

In this study, Algerian condensate gas over Ni/Al2O3 was used for the preparation of low-cost and pure carbon nanotubes through chemical vapor deposition. Response surface methodology was employed to optimize the preparation parameters, with the best conditions found to be a catalyst/condensate gas mass ratio of 5%, a synthesis time of 112 minutes, and a temperature of 1000 degrees Celsius. The high-quality CNTs produced under these optimum conditions had diameters of 10 nm, with a predicted carbon yield of 81.76%.