Control of carbon helix fiber formation and fiber composition over Cu/SrO catalyst mixtures

CuO and CuO/SrO catalysts with different Cu/Sr ratios were prepared by a co-precipitation method and calcined at 350 °C. Carbon nanofibers (CNFs) were grown over the reduced catalysts by chemical vapor deposition (acetylene/H2, 300 °C, 30 min). The TEM images of the CNFs revealed a mixture of straight and coiled CNFs with a broad diameter distribution (50–400 nm) dependent on the Cu/Sr ratio of the catalyst used. The as-prepared CNFs were characterized by TEM, XRD and Raman spectroscopy and the data revealed the highly amorphous nature of the CNFs. IR and TGA analysis revealed that the chemical composition of the CNFs changed as the SrO content changed. The SrO content also affected the Cu particle size and influenced the morphology of the Cu particles from which the CNFs grew.