Morphology of metallic nanoparticles as a function of deposition time in electroless deposition of metal on multi-walled carbon nanotubes

Morphology of silver (or copper) nanoparticles as a function of deposition time was examined in electroless deposition of metal on multi-walled carbon nanotubes (MWCNTs). Silver (or copper) deposited MWCNTs were prepared using successively, surface oxidation, tin-palladium activation, hydrochloric acid-acceleration, and ELD of silver (or copper). The results show that nanoparticles of face-centered cubic silver (or copper) were deposited initially on the interior surface of a MWCNT (similar to 50 nm in inner diameter) but later on its exterior surface. The percentage silver (or copper) in the coated MWCNTs increased from 7.0 (6.7) to 28.2 (25.5) wt.% by weight for a deposition time ranging from 3 to 10 min. The average diameter of silver (copper) nanoparticles increased from 1.3 (1.1) to 2.6 (2.3) nm, while the surface area and pore volume decreased from 261 to 144 (81) m(2)/g and from 1.02 to 0.38 (0.27) cm(3)/g, respectively. However, there was no silver deposition on the interior surface of a thin-MWCNT (similar to 50 nm in inner diameter) observed because the capillarity decreases with decreasing tube diameter. (C) 2008 Elsevier B.V. All rights reserved