Characterization of carbon nanofibers produced in the reforming of CH4 with CO2 over supported Pd

We have studied carbon nanofibers (CNF) formed in the reforming reaction of CH4 with CO2 over a Pd (0, 42%)/α-Al2O3 catalyst at 973 K. The obtained nanostructured carbon material was characterized by high-resolution transmission electron microscopy (HRTEM). The results showed CNF of well-defined structures with diameters between 8 and 18 nm. A fraction of these fibers showed branched structures. Our results suggest that the fiber grows taking the metallic particle off the substrate, that the type of fiber obtained is related to the particle shape and that the origin of fiber growth is the formation of graphitic sheets on the metallic particle surface.