Herein, gas phase synthesis and characterization of multifunctional core@shell, Au@TiOx
nanoparticles have been reported. The nanoparticles were produced via a one-step process using a multiple-ion cluster source under a controlled environment that guaranteed the purity of the nanoparticles. The growth of the Au cores (6 nm diameter) is stopped when they pass through the Ti plasma where they are covered by an ultra-thin (1 nm thick) and homogeneous titanium shell that is oxidized in-flight before the soft-landing of the nanoparticles. The Au cores were found to be highly crystalline with icosahedral (44%) and decahedral (66%) structures, whereas the shell, mainly composed of TiO2
(79%), was not ordered. The highly electrical insulating behaviour of the titanium oxide shell was confirmed by the charging effect produced during X-ray photoemission spectroscopy.
Schematic and principles of operation of MICS. (a) Two of the three magnetrons are presented as M1 and M2. These magnetrons are placed in the aggregation zone (AZ). (b) The growth of pure Au or (c) TiOx NPs was achieved using only one magnetron. (d) Growth of core@shell, Au@TiOx by combining both magnetrons.