Carbon nanotubes were modified by FeSO 4 - H 2 O 2 system,iron hydroxides were adsorbed on the wall of carbon nanotubes simulta neously.These precursors were treated at723K for2h under hydrogen,nitrogen and a ir atmo - sphere to prepare carbon nanotubes supported γ- Fe 2 O 3 catalyst,γ- Fe 2 O 3 and α- Fe 2 O 3 compound catalyst and amorphous Fe 2 O 3 catalyst,respectively.This is green method to prepare high Fe 2 O 3 loading( ≥ 50%)abstract:catalyst without adding other cation.The different structures Fe 2 O 3 catalysts can be synthesized by controlling the condi - tion of thermal treatment to content active phase requirements for different catalytic reactions.The paper presents a new method to prepare carbon nanotubes supported catalysts.
A series of LaAl 1-xFe xO 3 catalysts prepared with lanthanum nitrate, aluminium nitrate and iron nitrate was investigated in catalytical syntheses of carbon nanotubes with high yields and purity. The properties of carbon nanotubes prepared by the method of CVD(chemical vapor deposition) with n-hexane as the carbon resource were studied and it was shown that the diameter of carbon nanotubes can be controlled by the molar ratio of iron to aluminum in the catalysts and that the diameter of carbon nanotubes changes a little with the decrease of the iron content in the catalysts. From the TEM pictures of carbon nanotubes, it can be found that the LaAl 1-xFe xO 3 catalysts have a significant influence on the wall thickness of the carbon nanotubes, whereas they have little influence on the inner diameter of the carbon nanotubes.
Platinum nanoparticles supported on carbon nanotubes (CNTs) were prepared by the chemical reduction method in solutions. The effects of reducing process and chemical modification of CNTs on the sizes and dispersion of nanoparticles were studied with SEM, TEM and XRD. It was demonstrated that the chemical modification of CNTs could improve their compatibility with solvents, hence the dispersibility of the platinum nanoparticles on CNTs. Among different reducing agents, including EG, NaBH4, HCHO and Na2S2O3, the smallest size, about 2.5 nm, and best dispersion of platinum nanoparticles were achieved by using EG as reductant under similar preparation conditions. The Pt/CNT catalyst prepared by EG reduction on H2SO4-modified CNTs exhibited excellent electrocatalytic activity for the direct methanol oxidation.
