Growth of carbon nanostructures on carbonized electrospun nanofibers with palladiumnanoparticles

Abstract

This paper studies the mechanism of the formation of carbon nanostructureson carbon nanofibers with Pd nanoparticles by using different carbonsources. The carbon nanofibers with Pd nanoparticles were produced bycarbonizing electrospun polyacrylonitrile (PAN) nanofibers includingPd(Ac)2. Such PAN-based carbon nanofibers were then used as substrates to grow hierarchicalcarbon nanostructures. Toluene, pyridine and chlorobenzine were employed as carbonsources for the carbon nanostructures. With the Pd nanoparticles embedded in thecarbonized PAN nanofibers acting as catalysts, molecules of toluene, pyridine orchlorobenzine were decomposed into carbon species which were dissolved into the Pdnanoparticles and consequently grew into straight carbon nanotubes, Y-shaped carbonnanotubes or carbon nano-ribbons on the carbon nanofiber substrates. X-ray diffractionanalysis and transmission electron microscopy (TEM) were utilized to capture themechanism of formation of Pd nanoparticles, regular carbon nanotubes, Y-shapedcarbon nanotubes and carbon nano-ribbons. It was observed that the Y-shapedcarbon nanotubes and carbon nano-ribbons were formed on carbonized PANnanofibers containing Pd-nanoparticle catalyst, and the carbon sources playeda crucial role in the formation of different hierarchical carbon nanostructures.