Deposition of palladium nanoparticles on the pore walls of anodic alumina using sequential electroless deposition

Palladium nanoparticles were deposited using a sequential electroless deposition technique on the pore walls of nanoporous anodic alumina. For the particle deposition a Pd(NH3)42+ solution was soaked in the alumina membrane and a heated air flow was applied in order to reduce the palladium complex to palladium metal nanoparticles. By repeating the deposition process the size of the nanoparticles could be tailored in this investigation between 6 and 11nm. The size of the nanoparticles was also affected by the concentration of the Pd(NH3)42+ solution, i.e., higher concentration yielded larger particle mean diameters. The samples were investigated using high resolution scanning electron microscopy, x-ray diffraction (XRD), inductively coupled plasma with a mass spectrometer, high resolution transmission electron microscopy, and energy dispersive spectroscopy (EDS). Analysis revealed narrow size distributions of the particles as well as uniform particle coverage of the pore walls. No by-products were observed with EDS, and with the XRD analysis the metallic palladium crystallinity was confirmed.