PtxCuy@TiO2 nanoparticles by low-pressure plasma synthesis

A new and original method is presented to synthesize Pt, Cu, and Pt_xCu_y nanoparticles (NPs) anchored onto an inorganic nanopowder substrate (TiO₂), based on the plasma degradation, within an Ar/NH₃ radiofrequency plasma discharge, of solid organometallics (Cu and Pt acetylacetonate), mixed with TiO₂. Both chemical and crystallographic characterizations confirm the formation of metastable alloyed Pt-Cu nanoparticles. The difference of Pt and Cu concentrations in NPs measured with a volume technique (X-ray diffraction) and a surface technique (X-ray photoelectron spectroscopy) suggests a Pt concentration gradient within NPs attributed to a difference in organometallics degradation kinetics.