Over water-soluble alkali carbonate particles, coiled carbon nanofibers were produced in large quantities through the pyrolysis of acetylene at 450 degrees C. By controlling the component of catalyst, coiled carbon nanofibers and carbon nanofibers could be synthesized selectively. And the pyrolysis temperature also had a great impact on the yield and morphology of the obtained samples. By regulating the temperature, carbon nanofibers, carbon nanotubes and bamboo-like carbon nanotubes could be synthesized, respectively. Because the used catalysts were water-soluble alkali salts, the purification was very mild and high purity of carbon nanomaterials could be obtained expediently through a simple water washing process. The photoluminescence investigation indicated that the obtained samples exhibited a blue and two ultraviolet peaks, and the photoluminescence intensity could be enhanced greatly by increasing the excited wavelength. Therefore, the proposed route for the growth and purification of carbon nanomaterials is simple, environmentally friendly and low-cost. (C) 2015 Elsevier Ltd. All rights reserved.