Surfactant-assisted hollowing of Cu nanoparticles involving halide-induced corrosion-oxidation processes.
We have demonstrated a simple fabrication of hollow nanoparticles by halide-induced corrosion oxidation with the aid of surfactants. Cuprous oxide Cu2O nanoshells can be generated by simply mixing Cu nanoparticles with alkyltrimethylammonium halides at 55 degrees C for 16 min. The hollowing mechanism proposed is that absorption of surfactants onto the Cu surface facilitates the formation of the void interior through an oxidative etching process. Upon extending the reaction up to 4 h, fragmentation, oxidation, and self-assembly were observed and the CuO ellipsoidal structures were formed. The headgroup lengths of the surfactants influenced the degree of CuO ellipsoidal formation, whereby longer surfactants favored the generation of ellipsoids. Optical absorption measured by UV-visible spectroscopy was used to monitor both oxidation courses of Cu-->Cu2O and Cu2O-->CuO and to determine the band-gap energies as 2.4 eV for Cu2O nanoshells and 1.89 eV for CuO ellipsoids. For the contact-angle measurements, the wettability changed from hydrophilicity (18 degrees) to hydrophobicity (140 degrees) as the Cu2O nanoshells shifted to CuO ellipsoids.
Huang
Chih-Chia
CC
Department of Chemistry and Center for Micro/Nano Technology Research, National Cheng Kung University, Tainan 701, Taiwan.
Hwu
Jih Ru
JR
Su
Wu-Chou
WC
Shieh
Dar-Bin
DB
Tzeng
Yonhua
Y
Yeh
Chen-Sheng
CS
D001965:Bromides / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D003343:Corrosion; D057927:Hydrophobic and Hydrophilic Interactions; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000737:chemistry*; D014961:X-Ray Diffraction
D001965:Bromides; D002712:Chlorides; D013501:Surface-Active Agents; D003300:Copper