We have successfully prepared a face-centered cubic Au-Pd nanoporous structure (NPS) in a one-pot reaction under thermal decomposition of single-source precursor [Pd(NH(3))(4)][AuCl(4)](2). The precursor employed contains both desired metals 'mixed' on the molecular level, thus providing its significant advantages for obtaining alloys. The observation using a high-resolution transmission electron microscope has shown that the nanostructure was composed of interconnected polycrystalline ligaments with an average diameter of 14 ± 3 nm. The measurements made by energy-dispersive x-ray analysis and powder x-ray diffraction (XRD) confirm that the nanostructure consists of Au(0.67)Pd(0.33) alloy. In situ real-time synchrotron XRD was used to study the formation mechanism for Au-Pd alloy NPS. We provide the correlation of control parameters (such as temperature, rate of increase of temperature and gas atmosphere) with the microstructure and phase behavior of bimetallic products. Under reducing conditions (H(2) atmosphere) the first step is the formation of alloy nanowires. Finally, bimetallic alloy 3D nanostructure is formed after the complete decomposition of the precursor (100 °C).

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We successfully prepared face-centred cubic nanoalloys in systems of Au-Ir, Au-Rh and Au-Ir-Rh, with large bulk miscibility gaps, in one-run reactions under thermal decomposition of specially synthesised single-source precursors, namely, [AuEn][Ir(NO)], [AuEn][Ir(NO)] [Rh(NO)] and [AuEn][Rh(NO)]. The precursors employed contain all desired metals 'mixed' at the atomic level, thus providing significant advantages for obtaining alloys. The observations using high-resolution transmission electron microscopy show that the nanoalloy structures are composed of well-dispersed aggregates of crystalline domains with a mean size of 5 ± 3 nm. Еnergy dispersive x-ray spectroscopy and x-ray powder diffraction (XRD) measurements confirm the formation of AuIr, AuRh, AuIrRh, AuIrRh and AuIrRh metastable solid solutions. In situ high-temperature synchrotron XRD (HTXRD) was used to study the formation mechanism of nanoalloys. The observed transformations are described by the 'conversion chemistry' mechanism characterised by the primary development of particles comprising atoms of only one type, followed by a chemical reaction resulting in the final formation of a nanoalloy. The obtained metastable nanoalloys exhibit essential thermal stability. Exposure to 180 °C for 30 h does not cause any dealloying process.

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We have found that the thermal decomposition of [Ag-(O 2 C n H 2n−1 )] 2 , where n = 14, 16, 18, and 22, produces the ordered 3D nanostructure (supracrystals) directly during the chemical reaction, which makes it possible to obtain self-assembled structures in large quantities without requiring additional processing steps. The process of self-assembling of silver nanoparticles is characterized by TEM and in situ time-resolved SAXRD and WAXS data. The calculated unit-cell parameters of the fcc nanostructures formed correlate with the aliphatic chain length: these are 9.55 nm for silver myristate (n = 14), 9.8 nm for silver palmitate (n = 16), 10.46 nm for silver stearate (n = 18), and 12.5 nm for silver behenate (n = 22). Structural and morphological characteristics of supracrystals formed in situ during the thermal decomposition of silver carboxylates are found to be dependent on the sample heating rate. The self-assembled ordering of the silver nanoparticles was observed to begin at ∼180, and above ∼280 °C the supracrystalline structures begin to decompose.