Metal catalyst particles were created by ex-situ laser ablation for introduction into a reactive pyrolysis flame. By prior synthesis of the metal nanoparticles, the effects of the reactive gases can be clearly separated from the pyrolysis chemistry of a solvent carrier, as when using nebulized solutions. Moreover, varying reactivity issues associated with particle growth and size were bypassed. Fe selectively reacted with CO to produce nanotubes; while Ni selectively reacted with C 2H 2 to produce nanofibers. These observations were interpreted through donation and withdrawal of electron density between the adsorbate's molecular orbitals and surface atoms of the metal nanoparticle. The rate of reaction of nickel with only C 2H 2 was reduced in the reaction of C 2H 2 and cobalt with nickel. CO inhibited the Ni-catalyzed reaction. H 2 manifested an overall role of maintaining a catalytically active surface by etching of amorphous carbon or donating electrons to promote dissociative adsorption of coadsorbates. This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA, 8/22-26/2004).
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)