One-step preparation of feco nanoparticles in a SBA-16 matrix as catalysts for carbon nanotubes growth

Nanocomposites containing FeCo alloy nanoparticles dispersed in a highly ordered 3D cubic Im3m mesoporous silica (SBA-16) matrix were prepared by a novel, single-step templated-assisted sol-gel technique. Two different approaches were used in the synthesis of nanocomposites; a pure SBA-16 sample was also prepared for comparison. Low-angle X-ray diffraction, transmission electron microscopy and N ₂ physisorption at 77 K show that after metal loading, calcination at 500 °C and reduction in H ₂ flux at 800 °C the nanocomposites retain the cubic mesoporous structure with pore size not very different from the pure matrix. X-ray absorption fine structure (EXAFS) analysis at Fe and Co K-edges demonstrates that the FeConanoparticles have the typical bcc structure. The final nanocomposites were tested as catalysts for the production of carbon nanotubes by catalytic chemical vapour deposition and high-resolution TEM shows that good quality multi-walled carbon nanotubes are obtained.