Studies on the suitability of alumina as bimetallic catalyst support for MWCNTs growth in a CVD reactor

Abstract

The role of alumina (Al2O3) as catalyst support for improving the selectivity and uniformity in carbon nanotube growth via Chemical Vapour Deposition (CVD) technique has been widely explored. In this study, the suitability of bimetallic (Fe- Ni)/Al2O3 catalyst prepared via wet impregnation technique for the synthesis of multi-walled carbon nanotubes (MWCNTs) has been investigated. The surface morphology, thermal properties and the crystallinity of the bimetallic catalyst supported on aluminaand Multi-Walled Carbon Nanotubes (MWCNTs) were characterized using various analytical techniques such as HRSEM, HRTEM, EDS, SAED, TGA-DTA, and BET surface area. The results revealed that the synthesized catalyst wascrystalline with surface area of 286 m2 /g as determined by BET equipment. The bimetallic (Fe-Ni) supported alumina catalyst grown in a horizontal CVD reactor was found to produce high quality MWCNTs with 79.5 % purity. A Dynamic Light Scattering(DLS) based correlation chart revealed interdependence of length, diameter and aspect ratio of the purified and un-purified MWCNTs. This study has demonstrated that a thermally stable and high quality MWCNTs can be obtained from Fe-Ni/Al2O3 catalyst via wet impregnation followed by CVD technique