The development of intracrystalline mesoporosity within zeolites has been a long-standing goal in catalysis as it greatly contributes to alleviating the diffusion limitations of these widely used microporous materials. The combination of in situ synchrotron X-ray diffraction and liquid-cell transmission electron microscopy enabled the first in situ observation of the development of intracrystalline mesoporosity in zeolites and provided structural and kinetic information on the changes produced in zeolites to accommodate the mesoporosity. The interpretation of the time-resolved diffractograms together with computational simulations evidenced the formation of short-range hexagonally ordered mesoporosity within the zeolite framework, and the in situ electron microscopy studies allowed the direct observation of structural changes in the zeolite during the process. The evidence for the templating and protective role of the surfactant and the rearrangement of the zeolite crystal to accommodate intracrystalline mesoporosity opens new and exciting opportunities for the production of tailored hierarchical zeolites.

The Fe2O3 shell is in situ formed during the thermal annealing treatment and could effectively prevent the coalescence of Pd2FeCo nanoparticles. Moreover, Pd2FeCo@Pt/C exhibited excellent ORR and Zn–air battery performance, implying that the surface Pt plays an important role in enhancing the activity as well as preventing degradation.

Rapid developments of DNA-based assembly methods provide versatile capabilities in organizing nanoparticles (NPs) in three-dimensional (3D) organized nanomaterials, which is important for optics, catalysis, mechanics, and beyond. However, the use of these nanomaterials is often limited by the narrow range of conditions in which DNA lattices are stable. We demonstrate here an approach to creating an inorganic, silica-based replica of 3D periodic DNA-NP structures with different lattice symmetries. The created ordered nanomaterials, through the precise 3D mineralization, maintain the spatial topology of connections between NPs by DNA struts and exhibit a controllable degree of the porosity. The formed silicated DNA-NP lattices exhibit excellent resiliency. They are stable when exposed to extreme temperatures (>1000°C), pressures (8 GPa), and harsh radiation conditions and can be processed by the conventional nanolithography methods. The presented approach allows the use of a DNA assembly strategy to create organized nanomaterials for a broad range of operational conditions.

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear "pillar" morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.

In this research, high resolution transmission electron microscopy (HRTEM) and high angle annular dark field–scanning transmission electron microscopy (HAADF-STEM) studies of ceria(IV) oxide CeO2 nanocrystals (NCs) synthesized by a hydrothermal/two phase process were conducted. The synthesis route affords the possibility of controlling the shape of the CeO2 NCs by changing the oleic acid/cerium ([OLA]/[Ce3+]) ratio. At a relatively low [OLA]/[Ce3+] ratio of 4, a polyhedral NC morphology was obtained with {111} and {200} termination facets. Increasing the [OLA]/[Ce3+] ratio to 8, while maintaining a constant reaction time and temperature during the synthesis, truncated cube-like CeO2 NCs with {200}, {220}, and {111} termination facets was generated. These morphologies were identified by HRTEM and HAADF-STEM characterization. Fourier transform infrared (FT-IR) analysis and thermogravimetric analysis (TGA) confirm the presence of chemically bonded oleic acid (OLA) on the CeO2 NC surface. It indicates that there is a relationship between the bonded OLA and the shape of the NC. Additionally, the identification of concave surfaces on {200} facets by HAADF-STEM characterization suggests that the formation of the cube-like CeO2 morphology is a multiple step mechanism. On the basis of these observations new growth mechanisms for the CeO2 morphology variants are proposed.