The heat treatment duration effect on the efficiency of a catalyst for carbon nanotubes synthesis

Abstract

The present paper shows that the duration of the pre-catalyst heat treatment stage implementation for obtaining a metal oxide Co-Mo/Al2O3 catalyst through thermal decomposition has a significant impact on its effectiveness in the synthesis of carbon nanotubes (CNTs) via chemical vapor deposition (CVD). The size of active sites formed and the specific surface area of the Co-Mo/Al2O3 catalyst were found to depend on the pre-catalyst heat treatment conditions. It was experimentally proved that the characteristics of both the catalyst (specific surface area and efficiency) and the CNTs (diameter and degree of defectiveness) can be controlled by the mode parameters of the thermal decomposition stage. The research results confirm the possibility of obtaining an effective catalyst system without implementing the secondary heat treatment stage - calcination. Moreover, the use of the Co-Mo/Al2O3 catalyst, obtained according to this procedure, in the CVD process allows to reduce the cost of CNTs synthesized.