Formation Process of Mesostructured PtRu Nanoparticles Electrodeposited on a Microemulsion Lyotropic Liquid Crystalline Template As Revealed by in Situ XRD, SAXS, and XANES

We investigated the formation process of mesostructured PtRu nanoparticles electrochemically reduced on a microemulsion lyotropic liquid-crystalline (MLLC) template. Nonionic surfactant decaethylene glycol monohexadecyl ether (Brij 56) and heptane (2 wt %) were used to form the MLLC template of a 2D hexagonal packing. The MLLC template was proved to be more stable than the corresponding LLC one without heptane, in the uptake of the metal precursors and the accommodation of the subsequently electroreduced PtRu nanoparticles. Structural evolution from the metallic ionic precursors to the mesomorphically ordered PtRu nanoparticles as directed by the MLLC template was traced using in situ small-angle X-ray scattering (SAXS), in situ X-ray diffraction (XRD), and X-ray absorption near-edge structure (XANES) spectra, further complementary by energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and field emission transmission electron microscopy (FE-TEM). Integrated results indicate an ...