Effect of Reaction Time, Weight Ratio, and Type of Catalyst on the Yield of Single-Wall Carbon Nanotubes Synthesized by Chemical Vapor Deposition of Acetylene

Abstract

The single wall carbon nanotubes (SWCNTs) were synthesized by catalytic chemical vapor deposition of C 2 H 2 at 800 C for 30 and 60 minutes. The transition metals of Fe, Co, Ni, V, and bimetallic mixture of Fe-Co impregnated on MgO powder substrate with weight ratios of 1:100, 5:100 and 10:100 were used as catalysts. The effects of catalyst type, weight ratio, and the reaction time on carbon yield of SWCNTs were investigated. The statistical analyses showed that the 1:100 weight ratio of Co-MgO (60 min) had the highest carbon yield (55.99%). It was also found that the reaction time enhances the carbon efficiency of all catalysts whereas increase in weight ratio lowers the carbon efficiency for Fe, V, and Fe-Co; however the carbon efficiency of Co is not affected with change in weight ratio.

Investigation of the Effect of Reaction Time, Weight Ratio, and Type of Catalyst on the Yield of Multi-Wall Carbon Nanotubes via Chemical Vapor Deposition of Acetylene

“…The average ratios of intensities of D to G bands for Fe, Co, Fe-Co, Ni, and V catalysts are 1.02, Investigation of the Effect of Reaction Time, Weight Ratio, and Type of Catalyst on the Yield of MWCNTs 3 1.03, 0.89, 0.87, and 0.82, respectively. When compared to the I D /I G ratio of SWCNTs grown on same catalysts, the higher I D /I G ratio of the MWCNTs which may be attributed to higher content of amorphous carbon (24). These results show that MWCNTs grown on Co catalyst had the highest content of defects or amorphous carbon, whereas V had the lowest content.…”

“…Metal salts were used for the preparation of Fe, Co, Ni, FeCo, and V catalysts (24). C 2 H 2 was used as carbon source for MWCNT synthesis in the fluidized bed CCVD system.…”

“…In these studies, generally different substrate and source gases were used to investigate the parameters affecting the carbon yield. Therefore, as second part of our previous research we investigated the effect of different parameters such as reaction time, catalyst type, and weight ratio on the carbon yield of the MWCNTs with invariable substrate and carbon source (24).…”

“…In the Raman spectrum, the ratio of the intensities of the D and G bands (I D /I G ) is attributed to the amorphous carbon content and/ or the defect formation in the CNTs as D and G bands are related to the defects in the structure and degree of graphitization, respectively (16,25). Hence, the high I D /I G ratio shows the high content of amorphous carbon and/or defect formation in the structure (24). G 0 band that is observed »2700 band cm ¡1 is the overtone of the D band (26).…”

“…The weight loss between 300-400 C and above 400 C in the TGA graphs are attributed to the oxidation of amorphous carbon and CNTs, respectively (16). The carbon efficiencies of MWCNTs grown on all catalysts (Fe, Co, V, Ni, Fe-Co) were calculated as described in our previous study (24). The ratio of CNT to amorphous carbon (C amorphous ) and the catalyst were calculated as follows:…”