Design and assembly of ternary Pt/Re/SnO(2) NPs by controlling the zeta potential of individual Pt, Re, and SnO(2) NPs

In this study Pt, Re, and SnO(2) nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO(2) and Re/SnO(2) NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO(2). STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO(2) NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO(2) and Re/SnO(2) NP, as well as ternary Pt/Re/SnO(2) NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11051-018-4244-0) contains supplementary material, which is available to authorized users.