Synthesis and characterization of Pt–Cu bimetallic alloy nanoparticles by reverse micelles method

Platinum–copper bimetallic alloy nanoparticles were synthesized in water-in-oil (w/o) microemulsions of water/cetyltrimethyammonium bromide (CTAB)/isooctane/n-butanol by the co-reduction of H2PtCl6 and CuCl2 with hydrazine at room temperature. The samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectrum (XPS). XRD results show that there is only one peak in the pattern of bimetallic nanoparticles, corresponding to the (1 1 1) plane of the PtCu3 bulk alloy. XPS illustrates that both elements in the nanoparticles are in zero-valence and possess the characteristic metallic binding energy. HRTEM analyses confirm the formation of the PtCu3 alloy nanoparticles with a mean diameter of about 1.6 nm, where the corresponding lattice spacing of 1.87 Å is consistent with that of the (2 0 0) plane of PtCu3 bulk alloy. Moreover, the factors influencing the size of PtCu3 nanoparticles had also been investigated and discussed.