Influence of rare earth elements addition in layered double hydroxide catalysts on the yield of growing carbon nanotubes

Abstract

Efficient preparation of low-cost multi walled carbon nanotubes (MWCNTs) will make them more competitive in the application of lithium ion battery composite additives and conductive paste. For a long time, the catalyst with high activity is the key factor to prepare MWCNT. In this paper, rare earth elements (RE) were introduced into layered double/triple hydroxides (LDH/LTHs) catalyst for the first time to prepare a composite catalyst with high activity, and then MWCNT with high yield was prepared by chemical vapor deposition (CVD). Temperature and the introduction of RE elements will strongly affect the yield of MWCNTs. La, Ce, Dy and Pr can improve the catalytic efficiency of LTHs while Eu, Er and Nd reduce their catalytic efficiency. Specifically, the addition of Dy element can nearly double the productivity of CNTs at 650 °C, reaching to 3093 %. Further analysis shows that the strong magnetic effect of Dy element can surround the iron nanoparticles, effectively inhibiting the fusion of iron particles at high temperatures, and improving the catalytic activity of the catalyst.