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A precise investigation of NbO has been carried out by advanced electron microscopy combined with powder and single crystal X‐ray diffraction (XRD). The structure of pristine NbO has been determined as Pm‐3 m space group (SG) with a = 4.211 Å and the positions of Nb and O at the 3c and 3d Wyckoff positions, respectively, which is consistent with previous report based on powder XRD data. Electron beams induced a structural transition, which was investigated and explained by combining electron diffraction and atomic‐resolution imaging. The results revealed that the electron beam stimulated both Nb and O atom‐migrations within each fcc sublattice, and that the final structure was SG Fm‐3 m with a = 4.29 Å, Nb and O at the 4a and 4b with 75 % occupancy and same chemical composition. Antiphase planar defects were discovered in the pristine NbO and related to the structural transformation. Theoretical calculations performed by density functional theory (DFT) supported the experimental conclusions. [ABSTRACT FROM AUTHOR]

Gold nanoparticles have received much attention in recent years due to their unique size-dependent properties, as they find useful applications in materials science [Mayoral etal. (Nanoscale 2:335-342, 2010)], catalysis [Schwerdtfeger (Angew Chem Int Ed 42:1892-1895, 2003)] [Hashmi and Hutchings (Angew Chem Int Ed 45:7896-7936, 2006)] and biology [Sperling et al. (Chem Soc Rev 37:1896-1908, 2008)]. The preparation of such nanoparticles benefits from modern chemical knowledge, and a large variety of several procedures have been developed aiming at controlling the size and shape of these metal nanoparticles. Here, we show that two eighteenth-century recipes (Online Resource 1) used at that time to prepare drinkable solutions of gold, used as drugs, actually generate gold nanoparticles, clusters and even monoatomic species of gold. These simple methods involve the dissolution of gold in a solution of ammonium chloride in nitric acid (aqua regia) and the mixing of the resulting solution with rosemary or cinnamon essential oils. The complex mixture of compounds resulting from the fast reaction between aqua regia and the essential oils behave simultaneously as reductants and stabilisers of the nascent gold particles. These results not only prove that historical speculations on the presence of finely divided gold particles floating in these solutions were basically correct but they could also serve as a source of inspiration for new experimental approaches procuring the generation of stable sub-nanometer gold nanoparticles. Keywords Gold nanoparticles STEM Eighteenth-century recipes * Essential oil, There is a general agreement that the first scientific approach to the nature of what are now known as solutions of colloidal gold can be traced back to the works [...]

Incorporating hetero‐metal‐atom, e.g. titanium, into zeolite frameworks can enhance the catalytic activity and selectivity in oxidation reactions. However, the rational design of zeolites containing titanium at specific sites is difficult because the precise atomic structure during synthesis process remained unclear. Here, a titanosilicate with predictable titanium distribution was synthesized by mediating vacancies in a defective MSE‐type zeolite precursor, based on a pre‐designed synthetic route including modification of vacancies followed by titanium insertion, where electron microscopy (EM) plays a key role at each step resolving the atomic structure. Point defects including vacancies in the precursor and titanium incorporated into the vacancy‐related positions have been directly observed. The results provide insights into the role of point defects in zeolites towards the rational synthesis of zeolites with desired microscopic arrangement of catalytically active sites. [ABSTRACT FROM AUTHOR]

Herein, we show how electron microscopy can provide atomic-level understanding of FAPbBr3, where electron diffraction and high-resolution imaging were combined allowing not only the characterization of the pristine material but also the identification of different intermediates upon its structural disintegration. Additionally, a minor tetragonal phase was also identified whose structure was also solved. [ABSTRACT FROM AUTHOR]

Conventional separation technologies to separate valuable commodities are energy intensive, consuming 15% of the worldwide energy. Mixed-matrix membranes, combining processable polymers and selective adsorbents, offer the potential to deploy adsorbent distinct separation properties into processable matrix. We report the rational design and construction of a highly efficient, mixed-matrix metal-organic framework membrane based on three interlocked criteria: (i) a fluorinated metal-organic framework, AlFFIVE-1-Ni, as a molecular sieve adsorbent that selectively enhances hydrogen sulfide and carbon dioxide diffusion while excluding methane; (ii) tailoring crystal morphology into nanosheets with maximally exposed (001) facets; and (iii) in-plane alignment of (001) nanosheets in polymer matrix and attainment of [001]-oriented membrane. The membrane demonstrated exceptionally high hydrogen sulfide and carbon dioxide separation from natural gas under practical working conditions. This approach offers great potential to translate other key adsorbents into processable matrix. [ABSTRACT FROM AUTHOR]

The development of materials integrated with ultrasmall multi‐metal nanoparticles (UMMNs) and mesoporous zeolite is a considerable challenge in chemistry and materials science. We designed a trifunctional surfactant, in which the pyridyl benzimidazole in the hydrophobic tail generates the mesopores through π–π stacking; the diquaternary ammonium in the hydrophilic headgroup direct the formation of MFI zeolite sheets and the nitrogen atoms in the heterocyclic rings coordinate with various metal ions to form UMMNs confined in the zeolite matrix after calcination and reduction. A library of 56 UMMNs confined within both micropores and mesopores of MFI zeolites (MMZs) with 4 mono‐, 14 bi‐ and 38 tri‐metallic nanoparticles (sizes of 1.3–4.7 nm) of combinations of Rh, Pd, Pt, Au, Fe, Co, Ni, Cu and Zn were made. An improved catalytic performance was exhibited in the sequence of Rh‐MMZ

Herein we report the synthesis, structure solution, and catalytic properties of PST‐31, which has an unprecedented framework topology. This high‐silica (Si/Al=16) zeolite was synthesized using a pyrazolium‐based dication with a tetramethylene linker as an organic structure‐directing agent (OSDA) in hydroxide media. The PST‐31 structure is built from new building layers containing four‐, five‐, six‐, and seven‐membered rings, which are connected by single four‐membered rings in the interlayer region to form a two‐dimensional pore system. Its channels consist of [4.56.6.9.11] and [5.6.7.9.10.11] cavities and are thus delimited by nine‐, ten‐, and eleven‐membered rings. The OSDA cations in as‐synthesized PST‐31 were determined to reside without disorder in the large [42.514.64.72.94] cavities composed of smaller [4.56.6.9.11] and [5.6.7.9.10.11] ones, leading to a symmetry coincidence between the OSDA and the surrounding zeolite cavity. The proton form of PST‐31 was found to be selective for the cracking of n‐hexane to light olefins. [ABSTRACT FROM AUTHOR]