An effective synthesis of carbon nanotube foams over three ambient atmospherically calcined Fe–Mo/MgO catalysts: Structural characterization with growth mechanism

Abstract

Our research attempted to investigate the impact of calcination on the synthesis procedure, thickness dependency, and catalytic phases of carbon nanotubes (CNTs) exhibiting a foam-like design. The sol-gel technique of combustion was used to generate three different stoichiometric molar proportions of extremely active Fe:Mo:MgO catalyst significantly powder (namely 1:0.5:13, 1:1:13, and 1:1:50). The crystalline phases of the catalysts were modified by calcination under Air, inert (Ar) and reduced (H2) atmospheres. XRD, scanning electron microscopy (SEM), in addition to Energy Dispersive X-ray (EDX) analysis were utilized to examine the development of the catalytic compounds' morphological phases, size of particles, shape, and composition of elements.The crystalline shapes, sizes and other morphological characteristics of the highly active catalysts were studied by TEM. Additionally, the BET surface area as well as the average particle diameter, volume of pore, and radius of pore were ascertained using the N2 sorption isotherm evaluation. Then, the combination of uncalcined and calcined catalysts were employed to generate CNT foams through CVD approach. The CNT foam development findings were examined using a variety of physicochemical strategies. From these studies, we established the relation between the catalytic phases and the growth of MWCNTs with foam-like morphology. Finally, the change of the growth mechanism and diameter of the MWCNT foams over the active catalysts based on the stoichiometric molar ratios between the catalyst and support was analyzed through TEM studies.