Thermally induced transformations of Au@Cu2O core–shell nanoparticles into Au–Cu nanoparticles from temperature-programmed in situ powder X-ray diffraction

Seeded Growth of Au@CuxO Core-Shell Mesoporous Nanospheres and Their Photocatalytic Properties

We report a facile synthesis of Au@CuxO core-shell mesoporous nanospheres with tunable size in the aqueous phase via seeded growth. The success of the current work relies on the use of a halide-free copper (Cu) precursor and n-oleyl-1,3-propanediamine as a capping agent to facilitate the formation of a copperish oxide shell with a mesoporous structure and the presence of mixed oxidation states of Cu. By varying the amount of spherical Au seeds while keeping other parameters unchanged, their diameters could be readily tuned without noticeable change in morphology. As compared with commercial Cu2O, the as-prepared Au@CuxO core-shell mesoporous nanospheres exhibit the higher adsorption ability, enhanced activity, and excellent stability toward photocatalytic degradation of methyl orange (MO) under visible light irradiation, indicating their potential applications in water treatment.

Two-dimensional multimetallic alloy nanocrystals: recent progress and challenges

In this highlight article, the recent progress on the preparation and application of multimetallic alloy nanocrystals with 2D nanostructures is systematically reviewed, as well as perspectives on future challenges and opportunities.

Complex modeling for the quantification of nanoscale disorder using genetic algorithms, density functional theory and line-profile analysis

A new, computationally efficient, complex modeling approach is presented for the quantification of the local and average atomic structure, nanostructure and microstructure of an Au0.25Cu0.75 alloy. High-resolution X-ray powder diffraction and whole pattern fitting show that the sample is phase pure, with isotropic lattice strain and a distribution of equiaxed crystallites of mean size 144 (11) nm, where each crystallite has on average four twin boundaries and an average of three deformation faults per four crystallites. Both small- and large-box model optimizations were used to extract local and long-range information from the pair distribution function. The large-box, 640 000-atom-ensemble optimization approach applied herein relies on differential evolution optimization and shows that the alloy has chemical short-range ordering, with correlation parameters of −0.26 (2) and 0.36 (8) in the first and second correlation shells, respectively. Locally, there is a 1.45 (8)% tetragonal distortion which on average results in a cubic atomic structure. The isotropic lattice strain is a result of atom-pair-dependent bond lengths, following the trend d Au—Au > d Au—Cu > d Cu—Cu, highlighted by density functional theory calculations. This approach is generalizable and should be extensible to other disordered systems, allowing for quantification of localized structure deviations.