Growth of La 2CuO 4 nanofibers under a mild condition by using single walled carbon nanotubes as templates

Abstract

La 2CuO 4 nanofibers (ca. 30 nm in diameter and 3 μm in length) have been grown in situ by using single walled carbon nanotubes (SWNTs; ca. 2 nm in inner diameter; made via cracking CH 4 over the catalyst of Mg 0.8Mo 0.05Ni 0.10Co 0.05O x at 800 °C) as templates under mild hydrothermal conditions and a temperature around 60 °C. During synthesis, the surfactant poly(ethylene glycol)–block–poly(propylene glycol)–block–poly(ethylene glycol) and H 2O 2 were added to disperse SWNTs and oxidize the reactants, respectively. The structure of La 2CuO 4 nanofibers was confirmed by powder X-ray diffraction (XRD) and their morphologies were observed with field emission scanning electron microscope (FESEM) at the hydrothermal synthesis lasting for 5, 20 and 40 h, respectively. The La 2CuO 4 crystals grew from needle-like (5 h) through stick-like (20 h) and finally to plate-like (40 h) fibers. Twenty hours is an optimum reaction time to obtain regular crystal fibers. The La 2CuO 4 nanofibers are probably cubic rather than round and may capsulate SWNTs.